I believe we can all agree that the "instruments" that came with the many copies of Rock Band are... well, crap.
One of the largest problems is how loud the drum kit is, it can honestly piss neighbors off.
One rock enthusiast Brian Mentock set out to make rubber discs that stick to the pad, and make it both quieter and easier to work with. It's also supposed to give the pads a more realistic feel and sound then the usual loud CLAK CLAK CLAK CLAK CLAK that most people are used to.
Here's a video of someone playing Flirtin' With Disaster on Expert with the Rubber Pads.