I'm the "resident certificate girl" for my family. Many of the gifts my mom gives are things you can't really package and wrap...golf lessons, a day on a boat, massage, etc so when this situation arrives, guess who she enlists help from...ME! :-)
I've done certificates for a massage, golf lessons, and vacation voucher to name a few.
Just googled the specific theme border, copy and pasted into a word document and used a text box to get a little crafty with the catch phrase and wording.
Below are a few examples:
love you! :-)