Yeah, Leominster isn't exactly a hot spot.
Higgins is one of the world's premier collections of medieval and Renaissance arms and armor. Definitely worth the drive. While you are in Worcester anyhow, visit the Worcester Art Museum, their Italian Renaissance collection is world class and then some, they also have a very good egyptian collection.
Worcester also hosts the Worcester Polytechnicl Institute a truly excellent technology university. It's small but very high end. It has also got its own nuclear reactor.
Worcester is a highly under-rated city, both by visitors and, most importantly, by itself. It is horribly isolationist. What can you say about a city that refused to have the olympic torch pass through town out of fear that it would attract the wrong element? It is a community bent on self-limitation. But it's got some cool stuff.
Leominster's main industry is plastics. The smell can get annoying. A friend of mine owns a nice apple orchard in Phillipston called Red Apple Farm. It's a pick your own place, family run for 3 generations. Springfield Armory Museum in Springfield is a good idea, There is also the Smith and Wesson factory and range facility in Springfield. It is one of the few such facilities in the area, Most ranges in Massachusetts do not offer rentals or even public access.
Strawberry Banke in Portsmouth New Hampshire is a nice place to visit for history buffs, so is Plymouthe Plantation in Plymouth MA. which strives to present a realistic portrait of life in the 1627 Massachusetts Bay colony.
Boston is loaded with cool stuff to do also...if you can stand the city. I highly recommend the Bunker Hill monument and the presentation at the top of the Hancock Tower detailing the battle of Bunker Hill.
There is also "Old Ironsides" the oldest serving commissioned Naval Vessel in the US Navy. It served in the war of 1812. It is an excellent place to check out. The New England Aquarium is also an exceptional example of the type currently undergoing some updating. Then there is Quincy Market and Fanieul Hall, the center for a great deal of agitation in the pre-Revolution days. The Freedom Trail in Boston is, in general, an interesting way to spend a day. It'll take you by the Old North Church, Paul Revere's old home and through The North End, where some of the best Italian restaurants in America can be found.
While you are at it, right up Route 2 from Leominster is Concord, MA and a number of Battle Road museums. Many of the homes along the famous road have been restored and or preserved so that modern people can better understand the famous battle.