When traveling, crashing with a friend is great because it's cheap and offers many of the comforts of home, but crashing at a hotel's also great because no one has to actually like you. If you're broke and unpopular, use Airbed & Breakfast
Begun on a whim by a couple of SF "design-trepeneurs", A&B's a marketplace that puts spendthrift travelers in touch with equally spendthrift hosts in cities worldwide. If you're the former, type in when/where you're going, and A&B'll toss back a list of quick, GMapped descrips/per-night prices (e.g., "cozy spare room, $35", "PrivateApt, $95"); because it's relatively new, some cities'll have more hosts than others (NY's 25 vs Rio's 1, though it does offer access to a tub full of ice for the price of just one kidney). Click through for deets on the pad (bed type/max occupancy/wifi...), its keeper's habits (bedtime/job/cleanliness) and, more importantly, whether or not he'll be there; you can also contact the host directly with any additional q's, and once you've picked a winner, secure it via credit card -- as opposed to the traditional payment, daring tales of your adventurous travels/assurances that you will not put your penis in the three holes
Right now, A&B's ramping up outreach to make a splash at the Democratic and Republican National Conventions in Denver and St Paul -- you'll know they're accepting "soft money" when you find yourself bunked up in the Straight Talk Express.