(AP Photo/Lennox McLendon, File) FILE - In this May 14, 2013 file photo, Leonard Nimoy arrives at the LA premiere of "Star Trek Into Darkness" at The Dolby Theater in Los Angeles. Nimoy, famous for ...

One simple cameo for Leonard Nimoy resulted in one of the biggest 'Star Trek' crossovers, and now he's a staple of 'The Simpsons' and 'Futurama.' ...