What are some "green" Father's Day gift ideas?

make something from recycled materials.

How about a terrapass? If he doesn't drive, there's also ones for flight. www.terrapass.com.

I don't know what your dad's into, but my dad loves plants. Maybe a houseplant? That's gotta be good for the environment

This book: http://www.worldchanging.com/book/ He won't be able to put it down. :D

not necessarily good for the environment, but maybe the book "blue gold" about the water crisis! a real page turner.
if he's into green design, the website branch has a nice selection of sustainable gifts. (www.branchhome.com)
There are lots of eco-clothing lines like Edun that are great. get him a t-shirt or something.
A subscription to a CSA if he's a foodie (weekly delivery or pick-up of produce from an organic farm)

This wonderful site from another Fluther query....gifts in kind, if your dad has enough stuff of his own. Immunize a child, buy someone eyeglasses, float a very small loan, plant a tree, etc. http://changingthepresent.com/ also heifer.com. I gave 1/2 a llama in my mom's honor.

There's not a lot of time to shop online at this point, but this site may give you some good, funky ideas and then you can try and find them locally. Also, I've found that our Whole Foods has a great gift section and I've found some great green things there, as well. Also, many cities have monthly "subscriptions" to have organic produce delivered. Three months-worth may fit into your budget.

http://www.cribcandy.com/eco-friendly

Massage - no resources used and gets a man to relax and connect to his body. The planet needs more calm and centered men so they chill out and cooperate more with nature and their fellow human beings.

Experiences last forever