Pre-, post- and "Hell-no-I-won't-go-to" Coachella happenings offer a doozy of decisions for dance heads this week. For those staying in L.A., Saturday night looks hot (though not as hot — literally — as the dance tent in Indio will be). The alluring DJ Rap headlines Vanguard Saturdays, which has brought on promoters from Incognito to compete against the other Hollywood biggies that night (Décor and Avalon). Rap is touring in support of her new studio release, Synthesis (Ministry of Sound), a collection of melodic and rhythmic electronic dance blends that are sure to translate well in a club setting by her own hands. 6021 Hollywood Blvd., Hlywd.; Sat., April 17, vanguardla.com. Bad Boy Bill brings more purist Chicago house stomps and his charismatic style (rocking multiple turntables) to Avalon that same night. 1735 Vine St., Hlywd.; Sat., April 17, avalonhollywood.net. "Secret and surprise" DJ appearances are sure to douse L.A. after the desert music fest, but instead of wasting time figuring out what those might be, set the calendar for Ecco, where L.A. house legend Doc Martin promises one of his vigorous mixes of classic, tribal, acid and soulful house. EC Twins open. 1640 N. Cahuenga Blvd., Hlywd.; Wed., April 21, eccohollywood.com.