I guess we can blame Rocky Balboa and Indiana Jones and the Kingdom of the Crystal Skull for this. They proved that long-dormant franchises can be revived with some success.
TrackingB.com is reporting that Shane Black, writer of the first Lethal Weapon film, has written a treatment, if not an entire script, for a potential Lethal Weapon 5. Original producer Joel Silver is rumored to be on board as well.
It has been 10 years since Lethal Weapon 4 graced movie screens, which certainly is less than the 16 years between Rocky sequels and the 17 years between Indiana Jones movies, if that helps.
The plot is rumored to revolve around Martin Riggs who is finally about to retire from the force. However, one case not only delays his retirement, but causes him to pull his former partner Roger Murtaugh out of retirement to solve it.
Mel Gibson has been keeping a low-on-screen profile since his 2006 arrest for drunk driving–and the anti-semtic tirade that followed it. His last role was a bit part in 2004′s Paparazzi. Danny Glover however, has been a little more active. He appeared this year in the Michel Gondry film, Be Kind Rewind. Both are rumored to be interested in returning to the franchise.