Hi from the other corner of the continent.  I will be in Lake Tahoe for 3 nights and I am looking for stuff to do. I will be traveling with the wife, a 7 year old and a 5 year old. We will be there also with my brother-in-law and his children.

We would love to see some snow, they have never seen it (mine) and it would make their trip. Where should I go for snow to play that's accesible from where I am going? What other activities or places to see can I enjoy with the boys there?

I will be googling and trip advisor researching but I trust AR15.com'ers way more.

When are you arriving?

I've never been to Tahoe, I'm not sure why, but have spent a lot of time in the high Sierras.

I would rent a boat and cruise or fish (drowning worms) or both.

You can rent mountain bikes and use the ski lifts to take you to the top of the mountains and ride the bikes down the trails.  Then, repeat.

Go for a day hike.  Bring a day pack, food, WATER! and warm clothes.  Also, bring WATER!  and more water, too.

There will be so much to do.

A few words of caution but don't let this scare you off, you'll have a great time.

Altitude sickness is a real threat and can be either inconvenient or a real threat.  Even a mild case is simply no fun at all (crushing, debilitating headaches, nausea).  This can kill the trip for those affected.  Tahoe is relatively low (6,000 ft) but is no joke for those not used to it and everything goes up from there (8,000 - 10,000 - 12,000 ft is not uncommon).

Dehydration is also a real threat and couples into altitude sickness.   Drink, drink, drink, if you are peeing anything other than clear, drink more.  Drink as you are driving there to get hydrated and stay hydrated, even though you will have to stop for frequent restroom breaks.  It could save your trip.

ETA - Sunscreen and Chapstick

Not sure what snow is accessible now.  They'll know when you get there.  Weather was showing thunderstorms in the area for a few days.  Might be some lifts operating for recreational purposes.  The Donner Memorial State Park near Truckee has some interesting history, exhibits and a monument to the Donner Party showing the depth of snow during the winter the party was trapped in the area.  Interesting but pretty grim, too.

If they'd have had XC skis, no one would have died.

Probably a little late for snow in Tahoe and the immediate area.  Any precipitation will likely be rain and help melt snow.  That said, there may be some higher elevation areas close that might get snow or still have snow.  It won't be very fluffy, but white, cold and crunchy.  Watch out for the yellow stuff.

There is a pretty neat little railroad museum just down the hill in Carson City.  The Nevada State RR Museum, has done a notable job in restoring several engines, a McKeen Motor Car and other rolling stock to operating condition.  I'm pretty sure they have rides on weekends, and "Steam Up" days periodically where they have one or more of their steam engines up and running.  
http://nvculture.org/nevadastaterailroadmuseumcarsoncity/  (doesn't include enough information on the collection, and doesn't seem to have had it's operating calendar updated.)

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTVHjzUKXDtq1JEi0282GYO7i_VWJsT9nZREQcEJrprIWQ4lS3DKw

https://upload.wikimedia.org/wikipedia/commons/thumb/8/86/NSRRMCC031.jpg/1200px-NSRRMCC031.jpg

The State Museum up town is nice.  Has a small walk through mine in the basement.  The building was the US Mint where they made the famous Carson City silver dollars.

The Virginia and Truckee Railroad operates out of Virginia City about 30-45 minutes further east.    Just walking around Virginia City can be a lot of fun for kids.

http://www.visitvirginiacitynv.com/about-virginia-city.html

Take them on a little hike in Shirley canyon. Starts in the back right area of the village by the ropes course. You could certainly run into snow back there. It's also a cool hike next to a creek with a waterfall. Keep an eye out for ponderosa pines, they smell like butterscotch. Kids might get a kick out of that.

Truckee is a fun little town. The historic downtown area is cool and has an old jailhouse museum that is pretty neat. Interesting history in this town; Whole town burned down a couple times. Railroad was built by Chinese slaves. Donners ate each other.

Also, Lake Tahoe is an obvious choice. Tahoe city to emerald bay. Really cool. There are old Viking homes down in crystal bay. Worth checking out as well.

We just got back from Tahoe.  Stayed in a cabin at the north end in Carnelian Bay.

Good base of operations.  Relatively nearby is Squaw Valley,  As of last week, they are still skiing the upper reaches.  We took both the Gondola rides just for fun and views.

Second the Donner Pass Museum in Truckee.  Fascinating, but probably a little dry for small kids.

Also did Virginia City.  It's about an hour away.  Lots of shops and old time candy stores.

5 of us went on a 3 hour horseback ride out of Zephyr Cove (South Lake Tahoe area).  Had a couple of much needed veg-out days at the cabin as well.  We followed that by about an hour in the Hard Rock casino, just for fun and net loss

ETA:  Also took a 3 or 4 hour boat ride from Tahoe City (North end) down to Emerald Bay.  We got really lucky with the weather while we were there.