I've biked Orcas a couple of times. Id suggest renting bikes and riding around. The island is large and has some good roads compared to the other San Juan islands.
Obviously the park, and the peak in the park is the highest point in the San Juans (MT Constitution) so go check it out for the view. The only time I have seen a whale was when camping over near Doe Bay. Theres also a resort at Doe Bay with a spa and outdoor hot tubs you could check out if you are into that. If you use the tubs, hopefully youre ok with old naked hippies. They also have concerts here in the summer.
Go on a kayak tour. Probably end up getting fairly close to some wildlife. Dont go on a hayak whale trip, though. They tend to go to a spot they hope whales will come too and just wait around. You are just as likely to spot whales cruising around checking out other wildlife.
Think about chartering a sailboat with a captain. I've spent a lot of time sailing around the San Juans and its really gorgeous from the water. There's great wind so the sailing is fun, and you'll probably see a lot of wildlife, maybe some whales if you are really lucky.
Take the ferries to the other islands, Friday Harbor on San Juan Island is one of the most popular, and Roche Harbor on the other end of San Juan Island is cool too. Its really small, but go down and check out the boats.
if you are into scuba diving, go on a trip with one of the local dive companies, as there as some awesome spots to dive here. The water is cold, but amazing plant and animal life in this area.
[This message has been edited by youandwhosearmy (edited 1/16/2012 2:58p).]