Have any NHL players played in the NHL after being inducted into the Hockey Hall of Fame?

Mario Lemieux was inducted into the Hall of Fame in 1997, and he returned to play in 2000, and retired for the final time in 2006.  Gordie Howe, and Guy Lafleur also played in the NHL after being inducted into the Hall of Fame. 

At least one. Guy Lafleur was inducted in 1988 after being retired for 3 seasons, but returned to play in 1988 through 1991.

1979 - Gordie Howe was inducted in 1972. He came out of retirement for the 1973-74 WHA season to play alongside his two sons, Marty and Mark. Gordie was a two-time WHA FirstTeam All-Star and WHA MVP (1974) before returning to the NHL for one last season (1979-80) as a member of the Hartford Whalers.

1988 - Guy Lafleur was inducted in 1988. Guy played three additional seasons in the NHL, one with the Rangers and two with Nordiques, and tallied 52 goals over that period.

2000 - Mario Lemieux was inducted in 1997. Upon returning to the NHL, Mario won the Lester Patrick Trophy (2001), Olympic Gold Medal (2002), and averaged over one and a half points per game (more than any other player during that period).