well since this thread was brought back, and NZ was really interested in further answers...
.Go for a run or walk in the woods. put the cell phone on silent, get away from the noise and chaos of the electronic world and then just open your eyes and ears to the things around you.
Honestly? When I get bored I start walking around the city seeing what I can get into. Sometimes I'll walk into random buildings and try to meet the most important or highest level person there. I'll put on a fake persona and stay in character the whole time. Other interesting things to do:
Try the Morpheus Effect with friends (repeat about 4 or 5 actions in a row without ever noticing each other, Improv Everywhere has a video to demonstrate this)
Take your desktop computers and use them in Starbucks
Go to your nearest department store and go on a wild goose chase with one of the employees
Go somewhere with an elevator and have you and your friends walk in at different moments before the door closes, then never face the door. (This one is especially cool if done right, more often than not the people who watch you do it will copy you and turn their backs to the door.)
Get a bunch of signs and start advertising that some item of desire is being given away for free a block away from you, give covoluted information on how to get there.
Frequent forums, play video games, shoot a basketball in the driveway, toss a football with one of my sons, harass the kids who are peacefully trying to watch TV, blame them when the girlfriend wants to know why they're flipping out, plan to go to the gym but never actually go, look at houses for sale in preparation for buying my own home soon (2-3 years out now), look at cars in preparation for buying a new car soon (3-6 months away now), read books both in physical and e-book format, drink craft beers and admire/despise the taste in a true connoisseur manner, and whatever else I can get my hands on in this rinky dink scumbag city.
That about covers it, if I can come up with anything else I'll certainly share.