Three weeks ago I downloaded this egg timer for my desktop to remind me to get up and exercise once an hour starting at 10:30 and every hour till 2:30. I began doing 10 push ups, and 10 crunches. With the plan of upping my reps by 5 each week. Now I am up to 20 and 20 and it feels great. My goal is 50 reps of each 5 times a day. Couple questions for any personal trainer types - I need something for the legs. I cannot squat cause my knees are popping from 25 years of abuse. I ride my bike about 10 miles at a clip as it doesnt hurt the old knees. But im pretty busy outside of the office so that only happens about once a week. So any leg exercises suggestions would be appreciated. Also at what, if any point is doing too many reps of pushups/crunches "too many"?