I've learned something today. I do not ever want to have so many keys that I need to buy a special doohickey to store them.

The car key folds up into the fob, which I carry separately. The key ring has the house key, the laundry room key (I live in a three-family home and we each have a locking laundry room/storage area in the basement), the locker key for work, and my brother's house key (so I can look after his house when he is on active Reserves). I could leave my brother's key off, but I'm afraid I might misplace it.