I'm not a parent, but yesterday Rob told me about what seems like an amazing company - Toygaroo! Toygaroo offers an online toy rental system (similar to what Plum Baby Clothes offers for kid's clothes) whereby you add toys to your wishlist online and every other month you receive a certain number of toys based on your subscription package (details about packages here). When your kids tire of the toys, you return them to Toygaroo and receive new toys. There is a whole section about the sanitization process used by the company, which is obviously a concern.
You can watch an NBC news story about Toygaroo here. There is also a video on the website that highlights another great use of this service - you can have a box of your child's favorite toys delivered directly to your vacation destination so that the toys await you upon arrival (and you don't have to tote them on the airplane). Have any of you tried Toygaroo?