Complex sentence: RFK Stadium, the home stadium for D.C. United, played host to the 2007 MLS Cup--the third time RFK Stadium hosted the championship game, and first since 2000.
Split into simpler sentences: RFK Stadium, the home stadium for D.C. United, will host the 2007 MLS Cup. This will be the third time that RFK Stadium plays host to the championship game, and first since 2000.