Here's my recipe: buy a house. Spend all your money (please IRS, send me my tax credit ASAP, I need to replace the fridge!). Take several weekends and then a whole week to work like mad getting it fit for human habitation (at least, up to my standards). Since the kitchen is a disaster, don't keep much food beyond some pretzels in it... The result is real calorie cutting and a ton of physical labor. I'm down 15 lbs in 6 weeks, even with a nightly beer as a reward for the work and massive dinners to get some calories in me.
I've ridden my bike about 12 miles in this time. Well, my new commute will be 37 miles round trip, so that should help keep up with the weight loss. My new neighbors appear amused by my recumbent. Give me a year and they'll all be riding 'em!
Using a 100 lb floor buffer is a good core workout.