Using his noggin

Scruffy and I are having great fun together this summer,exploring some new parks. The downside to all our fun is that he's now bored to tears at the regular (read 4 blocks away,go every night) park. He perks right up at the 'fun park', which comes with a river, trees etc but is quite a drive.
I'd go there more but he's so DANG drooly in the car...yuck!
Anyway I find he has more fun if I make him use his brain, instead of just playing boring old fetch.
At the fun park,I toss the stick or ball into the bushes, the trees or the river and he has to go find it.
At the regular park, it's a huge field with a tiny stand of trees at either end.
Any suggestions as to how I can make regular park time more fun/challenging? Alternatively any suggestions for drool-proofing a car? I'd really like to see him use his brain, not just his legs.
Thanks!

Are there other dogs at the smaller park? If Scruffy is not food agressive/posessive, how about hiding treats while he's in a sit/stay or down/stay and have him find them? Or, again, put him in a stay, go to the other side of the park, and practice recall...don't forget to reward him with the yummiest treat when he comes straight to you without wandering around first. New toys always make for more fun...you can save tug games just for your excursions to this smaller park (make sure he knows the rules of the game first). With novel games, he'll associate this park with as much fun as the big one too.

penny,
the hiding treats is a good idea! I do that at home when it's too yucky to go to the park and he needs a bit of fun.
The park has lots of dogs but I can go when it's quiet.
He's not possessive about anything but sticks, which I promptly toss in the trash to prevent fights (at the small park).
The sit/stay/recall for treats..will definately do...he's not listening that well lately.
THanks for the ideas!

You can also get fold-up obstacles (tunnels and jumps) or make your own from Looney store finds...I have taught my two to run through nylon laundry bags for treats at the end! Like the Top Dogs! :thumbs up

TacoGrl,
I had thought about making my own agility course, as I have a biggish yard.. You've given me some good ideas. Thanks!