I was stuck at work for 4 days during a nasty snowstorm. I called and left a message on the machine for my kitty so he could hear my voice. (The apartment complex was kind enough to feed him while I was away).

I also sing to him:
(To the tune of "I'm a Girl Watcher")
I'm a purr monster
I'm a purr monster
Purring all the time
Mao Mao Mao
I'm a purr monster
I'm a purr monster
Purring all the time
Mao Mao Mao