The Libertine Bar may have the Best Bar Food in Dallas, along with a great selection of beer and wine--and, of course, the monthly Playlister P local-music DJ nights. But beginning at 7 p.m. tomorrow night, the bar's brain cancer awareness event gives yet another reason to love the Lower Greenville pub. After a friend of the bar was diagnosed with Stage 4 brain cancer, the staff organized an impromptu concert with a live and silent auction to raise funds for her walk Saturday at Trinity Park