Here's another version of Murphy's Law for the milspouse:
When your husband has been deployed for three weeks with limited communications options so far, and he finally gets a computer and gets to IM for the first time of the deployment...your doorbell will ring and your phone will ring twice during his allotted 30 minutes of chatting.
And the phone will be someone important, like your OB nurse, so you will have to take the call and multitask.
Naturally, you've been sitting by the phone all day and haven't had anyone call you...until it matters.
Thanks a lot, Murphy.