Getting to the airport generally starts your journey off with a bitter dash of suck -- cabs drain your wallet, while rides from friends create a debt that when called in will leave you apoplectic with rage. For a more appealing option, try Hitchsters.
Started in NY and now serving SFO, San Jo, and Oaktown, Hitchsters is a free web service that pairs you up with another airport-bound human, then dispatches a towncar to swoop you both up; you'll have already paid, with Hitchsters automatically splitting the fare + tip evenly, even if you ordered the lobster. Simply enter your pertinent deets (address/phone/when & where you're going), and 48hrs before your flight, Hitchsters confirms your match based on proximity, flight-time, and whether or not you've specified your companion's gender (an option probably intended for women who feel more comfortable with other women, but why not abuse it, seeing as you're leaving town). Upon your return, Hitchsters'll go so far as to pair you with a suitable companion from your flight, so even if it's delayed you're guaranteed the company of someone at least as furious as you.
After all's said and done, you're asked to evaluate the car service and your companion with a thumbs up or thumbs down -- a reasonable request, assuming you're not stuck driving some jackass friend to the airport.