Google "Linda Tellington-Jones". You will find something about the "T-Touch".
There is one book about that on humans (it'smostly about horses, dogs etc). Find that one.
I think it's some guite to calming massage. Thinking of it for my missus for christmas, since she loves massage.
Just an idea, and she'll never be able to know what she's getting:D
As for just today, oh dear. If she's a reader, a seriously good book. If she's complaining about you having to little time together, take her out. Basically aim for her interests though.
Hope it helps.
BTW, my last birthday present for the missus was (together with many family members, forming the necessary funds)....a greenhouse. Currently fixing it, for it blew over in a hurricane
Next one might be a hot-pot.
Anything for the missus....!