Discovery Channel takes over the Greek Theater Wednesday night for a concert and party to tubthump the June 4 debut of its Planet Green channel (the channel formerly known as Discovery Home). Perfs are skedded to include Ludacris, Tommy Lee, ZZ Top's Billy Gibbons, Blue Man Group and others. Proceeds will go to a fund established to help rehab areas around Griffith Park that were torched by recent wildfires....

Thursday's a day for serious yakking. In the afternoon, the Hollywood Radio and Television Society hosts a luncheon event at the Beverly Hilton devoted to how the biz can help keep health care issues at the top of the nation's public policy agenda. Sally Field and Jeffrey Katzenberg are set as speakers. Leeza Gibbons will moderate a panel that is set to include top showrunners of shows that work in scrubs: Neal Baer of "Law & Order: SVU" (who really is a licensed physician), Bill Lawrence of "Scrubs" and John Wells of "ER"... In the evening, the Academy of Television Arts & Sciences parses LGBT issues in TV with a sesh at its North Hollywood HQ that will include thesps Billy Baldwin, Billy Crystal, Ron Rifkin, "Dirty Sexy Money" creator Craig Wright and Showtime's Robert Greenblatt. Bruce Vilanch is sure to keep things interesting as moderator...

On Sunday evening, Elmo's in town for the fourth annual presentation of the Fred Rogers Memorial Scholarships, also at the Leonard Goldenson Theater at ATAS' NoHo home base. Three $10,000 scholarships will be presented by ATAS and Ernst & Young to three grad students pursuing careers in children's media, in honor of the late host of PBS' enduring "Mister Rogers' Neighborhood." Also on hand for the 5 p.m. presentation will be Mrs. Mr. Rogers, Joanne Rogers, and actor David Newell, aka Mr. McFeeley.