I can tell you what I did with my kids--
I read to them a lot, we played games together, did art like painting and playdoh. We went to the park to ride tricycles and blow bubbles. Being part of a playgroup was good at that age because it gave me some adult interaction while the kids ran around and tired themselves out.
When they were a little older it got easier, they were able to entertain themselves more. Building toys are great (like Lego Duplo, etc.) and things like LeapPad are good for when you need to cook dinner or take a shower
I hope this is helpful--I know exactly what you mean "One is enough", especially at that age. I didn't get brave enough to try for a second child until my DD was 3. So take heart, she won't be this exhausting forever.
