I had a huge fear of heights to the point it was hard to drive on high bridges. A buddy took me sky diving a few years back and it was the scariest thing ever. I got got over my fear of heights after that.

She's a jerk. I would have said thanks and taken them and then sold them or tried to return them.

Keep them and give them away to someone else. Don't give her the satisfaction, she knew what she was doing when she bought them!

pray her parachute doesn't work

Get tickets for yourself for her favorite band on hers.

She did it on purpose -_-

Go anyway out of spite and get a picture of yourself sitting crosslegged in the air with your middle fingers out. Send it to her in a card that says "Thinking of you"

YDI because this isn't a very big deal. I mean, she is the one who bought the tickets. You didn't want to use them, even though she offered. Cut her some slack.

Tell her you will give the tickets to your best friends

It was probably her idea from the start. I'd show them that I could do it-- or if not, give them away to some other couple in front of them.