If you think my cakes are good, you ought to see DW's and stealth's! They make mine look very amateur.
Right, teddy bears picnic parties... I did one for DD's 2nd birthday in December and it went down really well. I had children from 6 months to 13 years and everyone seemed to enjoy it. I was going to make invites but ran out of time and found that buying Teddy themed invites was fairly easy too. There were loads of teddy themed plates, cups and napkins availbale online and I added some cheap, disposable, red checked tablecloths that added a real picnic feel. We had balloons and bunting too.
For food we did little triangle sandwiches, chicken nuggets, tray pizzas, Pom bears (of course) and some crudites and fruit to go with the cake - which was a cheap Costco one that I just decorated.
For games we just did pass the parcel as I wasn't sure DD would cope with many more and then did craft activities to fill the rest of the time. We had colouring and teddy bear biscuit decorating. You could also do pin the nose on the bear and good old musical statues to some teddy bear music. We got "The Many Songs of Winnie the Pooh" which did most of the party and fitted in well.
For party bags, I found it really hard to find something that would suit everyone because of the huge age range so I did little plastic cones of sweets tied with some pretty ribbon and a little teddy bear reflector keyring. They went down really well and were very cheap as the sweets all came from Costco too.