I usually clean during the daytime when the kids are in school because I work in the evenings. I'm so pooped after the kids are down at night that I don't have the energy to clean, but it's easy to sit at the computer and work.
On the weekends I never get any cleaning done other than laundry because our weekends are jam packed with activities from morning til bedtime. Needless to say come Monday morning, our apartment is a mess!
When do you clean?