If you and your Partner are both fairly techno-savvy (enough for Email, anyways), I recommend picking a day to play an email game. The rules are simple: you send a racy email that is only one line long. You can decide to go with what your partner says, or start something new. Par example:

God, I want to place my hands upon your fuckin' sexy ass and squeeze...
I want to breathe and moan softly into your ear as we thrust against eachother.
Running my fingers through your hair, I look into your eyes as I breathe into you, sofly pushing in until urgency overtakes us.

If you work a desk, it's something you can do from there - it's simple and effective and very exciting...

Enjoy!

[Note: I did not come up with this - it was Pamela all the way. She's a goddamn superstar.]