Pontiac Silverdome, Pontiac, MI. Opened in 1975. Former home of the Detroit Lions and Pistons, with a capacity of 80,000. The Detroit Pistons once played a basketball game before 61,000 there. The Lions moved to Ford Field in 2002. The arena sold for $583,000 in 2009. Now the site of monster truck rallies.
Houston Astrodome, Houston, TX. Opened in 1965 and former home of the Houston Astros and Oilers. The Houston Astros moved to Minute Maid park in 2000, and the Oilers moved to Tennessee in 1997. The new Houston Texans moved to nearby Reliant Stadium in 2002. It now sits abandoned waiting to be demolished.
Pyramid Arena, Memphis, TN. Opened in 1991, and used by the Memphis Grizzlies (NBA) from 2001 until 2004, when they moved to the FexEx Forum. Plagued with problems, it is now a sporting goods mega-store.
Robert F. Kennedy Memorial Stadium, Washington DC. Built in 1961. Former home to Redskins, Senators and Nationals. The Redskins moved to what is now FedEx Field in 1997. The Nationals moved to Nationals Park in 2008. A soccer team, DC United, still plays there.
Olympic Stadium, Montreal. Opened in 1976 for the Olympics and then home to the Montreal Expos, before they moved to Washington in 2004. Now occasionally used for rock concerts and Grey Cup playoff games. The total cost of the stadium when it was finally paid off was $1.5 billion, making this the second most expensive stadium ever built. It would cost $700 million to demolish it because explosives could not be used.
Maple Leaf Gardens, Toronto. Built in 1931 and home to the Maple Leafs and Toronto Raptors (NBA) until 1999, when they moved to the Air Canada Centre. It then sat empty for about a decade until being converted to a grocery store and athletic facility.
Alamodome, San Antonio, TX. Opened in 1993, and used by the San Antonio Spurs until 2002 when they moved to the AT&T Center. It has a capacity of 65,000 for football, and was used for 3 home games by the New Orleans Saints in 2005. Now it sits mostly empty, hoping for an NFL team to move there.
Compaq Center, Houston. Opened in 1975 as a multi-use sports facility and home to the Houston Rockets until 2003, when they moved to the Toyota Center. Now it is used by Lakewood Church, where Joel Osteen is pastor.
The Forum, Inglewood, CA. Opened in 1967, it was home to the Lakers and Kings, until 1999 when they moved to the Staples Center. Used for a church for about 10 years, it is now empty except for the occasional rock concert.
Sprint Center, Kansas City. Opened in 2007 in hopes of luring an NBA or NHL team, it hosts an Arena Football League team.
Kemper Arena, Kansas City. Opened in 1974 and home to Kansas City Scouts (NHL) and Kansas City Kings (NBA). The scouts moved to Colorado in 1976, and the Kings moved to Sacramento in 1985. It is now empty, waiting to be razed.
Amway Arena, Orlando, FL. Opened in 1989, and home to Orlando Magic. Replaced by the Amway Center. Will be imploded in March 2012. UPDATE: was demolished on March 25.
KeyArena, Seattle, WA. Opened in 1962 and home to Seattle Supersonics, who moved to Oklahoma City in 2008. Still used for university basketball and WNBA Storm.
Tacoma Dome, Tacoma, WA. Can seat 17,000 for basketball, and hosted the Seattle Supersonics in 1994. Now used for the occasional rock concert and RV shows.
Portland Memorial Coliseum. Opened in 1960 and home to the Trailblazers until 1995. Still used for minor league hockey. Will undergo a $30 million renovation.
Metrodome. Minneapolis, MN. Opened in 1982. It is still used by the Minnesota Vikings but it is considered obsolete. The Vikings have been trying to get a new stadium built since 2005 to no avail and they may move to Los Angeles. UPDATE (9/17/2012): will be replaced by Vikings Stadium by 2016.
Bush Stadium, Indianapolis. Built in 1931 and used by the minor league Indianapolis Indians. Abandoned in 1996, it sits empty while the city decides what to do with it.
Cooper Stadium, Columbus, Ohio. Built in 1931 and used by the minor league Columbus Clippers until they moved in 2008. Now abandoned.
Bernie Robbins Stadium, Atlantic City, NJ. Opened in 1998 and home to the minor league Atlantic City Surf until they folded in 2008. Now abandoned and rapidly deteriorating.
Compadre Stadium, Chandler, AZ. Opened in 1986 to host spring training games for the Milwaukee Brewers, until they moved in 1997. Today it is unused and in a state of disrepair.
Homestead Sports Complex, Homestead, FL. Built in 1991 as spring training field for the Cleveland Indians. Destroyed by hurricane in 1992 and the Indians moved. Rebuilt in 1993 in hopes of attracting another team, but has been empty ever since.