Good thread!
I haven't been leaning on the TV too much more than usual at this point, because, honestly, I know I'm going to *really* need it once the babe is born and my kids go on spring break, so I'm trying to stay really disciplined about it for now.
Speaking of TV though, do you guys have any of the Scholastic Books DVDs for kids? It's a series of like 20 DVDs, each one are animated versions of classic children's books. They are great and my kids LOVE them. And I consider them (almost) guilt-free TV, since it's kind of like having books read to them. I highly recommend them!
As for other projects, anything crafty will occupy my kids. Playdough is a big one, as is the sculpy clay (the kind you bake in the oven). My kids love to make snakes and bugs and little animals out of sculpy, and then play with the final, baked products. No mess, 15 min of baking. It's a good one.
Another thing they love: go out and buy a roll of the brown craft paper from Home Depot or something (it's used to protect floors and the like during construction). I roll out a big sheet of that (like 6-10 feet long) and the kids will draw a city, with buildings and roads and such. That occupies them for a goodly while. And then they will play on it with matchbox cars. And a roll of that stuff will last you a year.
Buy one of these knives:
http://www.livingplaying.com/hi4406.html. It's a kid-safe knife, but sturdy enough to chop vegetables, nuts, whatever. Give your kids a pile of carrots, celery, cucumbers, whatever, and ask them to make their own snack or chop up vegetables for a soup or salad. This is one of my kids' hands-down favorite things.
Give them a big bag of fabric remnants and scraps (or an old sheet they can cut up), a roll of masking tape and a stapler and tell them to make their own clothes. This will occupy older kids for an hour, guaranteed.
My last resort: put them in the bathtub. Let them play in there until they're wrinkly. Bring in a few pillows for yourself and stretch out on the floor with a magazine while they play. (Assuming of course your kids are old enough to be in the tub without you hovering.)
These are a few of my tricks.