Because I am a glutton for self-punishment, I have adopted two collie mixes ... Rubi came home with me from the Humane Society 2 1/2 years ago as a 3 month old puppy, and she is MY GIRL. She is not a dog, she is a person.
Reno joined us from the border collie rescue in October. He's about 1-ish, and completely doofy. We think he's part springer spaniel but he's definitely got lots of border collie too. They told us retriever mix, but I saw a pick of a b/w springer and it looked just like his little face.
Rubi is IN CHARGE, but they love to tussle and play. It's pretty funny because Reno LOVES tug-of-war, but I never really played that with Rubi, so she doesn't know how to do it. She always lets go and he runs around like, "What's wrong, we're not done yet!"
They wrestle a lot too. I gave up trying to keep them clean because they are always covered in each other's slobber.
Neither really fetch very well, which is weird for border collie mixes. I had to teach Rubi how. She does like the frisbee, but only for about 4-5 throws, and then she's done. She'd rather just run around. I tried flyball with her and it went OK, but we ran out of time ... I should get back into it.
My fiance and I each have a Jeep (I do NOT ride passenger) and we usually go up somewhere we have the place to ourselves, so we can let Rubi run along. We haven't done this with Reno yet. He doesn't come to his name, so we have some work to do before that can happen. He is coming along well at home, but I haven't tested him where there are distractions yet. He is young enough to be mostly brainless still. I don't think Rubi had ANY attention span until fairly recently.