Edit: Here's another Instructable on repairing the strum bar for a Rock Band guitar.
Step 1: Whammy Bar Not Springy?
Step 2: Broken Kick Drum Pedal? Kit Sliding Across the Floor?
As well, the kit had been sliding across the linoleum floor, a mouse pad (neoprene side down) under each of the corners helped with that. Of course you can also just play with your other foot (the one not playing the pedal) on the corner.
Step 3: Drum Pads Too Noisy, or Getting Worn Out?
There's also a mono headphone splitter that the kick pedal is plugged into for when we hook up a second pedal. It does work, but only one pedal can be down at a time.
Not shown is the broken Guitar Hero World Tour drum stick that we repaired by wrapping tape around.