I might get beat on for this, but: You could just remove the straps and clips, and leave just the flat pedals installed. As long as you have a brake or two installed, you'll be fine- you just wont be potentially able to generate as much power.

Before I started running clipless shoes/pedals (the kinds that snap together mechanically), I (usually) rode fixed with no retention. I hate clips and straps and/or I'm an uncoordinated dummy.