This will work wonders for your abs;
1) Shop at your nearest grocery store (NOT by car)
2) Take the trolley home with you (this is worth pledging your Union card for, students)
3) Empty the goods into your dwelling
(2 and 3 may provide exercise in itself!)
4) Take the trolley back - like this:
Jump up and land, belly down, on the handlebars. This may hurt even people of my stature, so you'll need to press your abs against the handlebars, and hold on to the rails as far to the front of the trolley as you can. Then you kick off and roll! The whole way to the shop. If it's all downhill, like it is for me, it's like rollerskating only less controllable and possibly less stylish...
This, by the way, will also give any spectator fab abs - they'll be laughing all the way home...
Now, depending on what groceries you bought and / or who devours them, this will easily outshine any old spinning or aerobics class! Yes, I have tried. (The trolley thing, that is...)