NEW YORK When Woody Harrelson opened the O2 Oxygen Bar on Hollywood's Sunset Strip, all of Southern California's airheads lined up to get a whiff. Now Oasis can bring the pure stuff to a special event via their portable oxygen bars. Sniffing the pure gas through tubes is said to calm the nerves, heighten awareness and provide a nice buzz that lasts longer than alcohol, sans the hangover. Oasis' oxygen also comes in flavors--each stimulates a different feeling, whether it's refreshing, equalizing or cheering. (We've seen the bars draw lines at trade shows.) And if you thought air was free, you were wrong: prices vary depending on location and event size, but a fully-staffed oxygen bar will cost about $1,500 per day.