First challenge of 100 Day Challenge

Alright. The 100 Day Challenge is going well. I've worked out three days in a row. I ran on Tuesday, then hit the gym Wednesday and Thursday. Now it is Friday. Normally a day off for me. I have to figure out a 30 minute workout of some sort. Do I go to the gym after work? Do I use my little stationary-type bike at home? Do I go for a walk?

This is going to be a toughie for me. What do you do for exercise on Fridays? Do you work out or do you take it easy since it's the start of the weekend?