What are some good drills to do when shooting my rifle at a 25yd indoor range? I don't have any outdoor ranges close to me. Rapid fire is not allowed, but they let doubletaps slide usually. I have already seen rifleman2000's first two drills, those sound good. Anything other good drills?

Something simple, Like practise coming up from the low ready, and getting the shot away as fast as possible, but still inside the "A zone"
How fast can you bring up the rifle, acquire, and slap a shot away that connects in the vitals.

(Ie. reaction speed drill)

This and throw in a speed reload on the end for added training.

Does the range have a couple of lanes with turners?  One drill I do a lot (working at an indoor range, I shoot a lot at 25 and under), is setting the turner to face for about 2 seconds, side for 2.5 seconds, and repeat for 20 cycles.  Then I put 10 rounds in each mag so I have to do a mag change on one cycle for added challenge.  It can also be changed up, the facers can/will turn the target 'back" to me, for adding in decision making, or I'll set it for 30 cycles, and put 14 rounds in one mag, 16 rounds in the other, and not know when it's going to run out :)  Start this at pistol range (7-10 yards) and work out until you consistently put controlled pairs into your targeted zone.  

Indoor is also a good area to work on your weak side shooting.

Spray paint some 6" dots on a target and some 10" dots. Practice keeping all your shots in the 6" at ranges 5-15 yards and in the 10" dot at 25 yards. You can get a lot of dots on a target so you don't have to change targets very often.

it was passed on to me, now passing unto to you:

shapes...stencil/ draw shapes on target.

with a buddy system, have your buddy call the shape and shoot as fast as you can

http://imgur.com/2mGEcCh

Transition to pistol

Mp 15-22 and shoot cheap