If you live in DC, Denver, Dallas, Chicago, Miami, LA or San Fran then why don't you check out the Green Apple Festival this Sunday? Looks pretty cool, im sure it will bring out all the dirt worshipping treehuggers (and treethuggers like me).
In Denver I will get to see The Neville Brothers, The Benevento/Russo Duo, Rose Hill Drive (Acoustic), and The Heyday.
The D.C. lineup looks the stongest to me, but seeing Menudo in Miami could be cool as well:
Washington D.C. Earth Day 2008 on the National Mall
The Roots & Friends, featuring Doug E. Fresh, Ne-Yo, Talib Kweli, will.i.am, Chrisette Michele and more, Gov't Mule, Umphrey's McGee, O.A.R. (special acoustic kickoff set), Thievery Corporation (DJ Set), Toots & The Maytals, Warren Haynes Solo Acoustic, Special National Anthem performance by American Idol winner Jordin Sparks
New York City (Central Park)
Ricky Skaggs & Kentucky Thunder, Big Head Todd and the Monsters, The Bacon Brothers, Vusi Mahlasela, Vienna Teng
Miami FL (Bicentennial Park)
Menudo, Arrested Development, Baby Loves Salsa featuring Jose Conde, Caravan of Thieves
Chicago IL (Lincoln Park Zoo)
Bill Kreutzmann (Grateful Dead), Oteil Burbridge (Allman Brothers), and Scott Murawski (Max Creek),Dirty Dozen Brass Band, Meshell Ndegeocello, Bassnectar, Chicago Afrobeat Project, Miss Lori Holton Nash (PBS Kids), The Gwalla Gwallas
Dallas TX (Fair Park)
Los Lonely Boys, Martin Sexton, Junior Brown, Cas Haley, The Steps, George Stanford
Denver CO (City Park)
The Neville Brothers, The Benevento/Russo Duo, Rose Hill Drive (Acoustic), The Heyday
Los Angeles CA (Santa Monica Pier)
Taj Mahal & Friends, Ziggy Marley solo acoustic, Juliette and the Licks, Escalera, (featuring Danny Way and Bob Burnquist), School of Rock Hollywood Allstars, The Frequency, Coby Brown
San Francisco CA (Golden Gate Park)
Mickey Hart’s Mass Drums (featuring Mickey Hart, Jon Fishman, Tommy Lee, Sikiru Adepoju, Bobi Cespedes, Rebecca Mauleon, Rhythm Village, Loco Bloco and more!), Yonder Mountain String Band, Dan Hicks and The Hot Licks, (featuring Michael Kang of String Cheese Incident), Brett Dennen
There are also a slew of concerts at venues in these cities all weekend. Check out the full schedule.