These are my goals for a basic exercise regimen:
Walk for 30 minutes at least 4x per week in the afternoon. If the weather is bad I stay in and dance around to music while kids are napping and otherwise occupied. Many times the baby is up to watch me though.
Strenght and stretching exercises 3x per week in the early morning.
Strengthening and toning exercises include: push-up type exercises (until I can do actual push-ups), a few simple pilates exercises, and crunches.
For stretching I basically get up, sit on the floor, extend my legs to the front or side, sit with my legs crossed, reach over with my arm, move any way that I feel like stretching. The main thing here is to get up and start moving in ways that stretch and strengthen my body. Pretty simple. Now I just have to stick to it.