Thread: Training?

I'm worried about Gryfn and Charlie Brown getting outside (Charlie headed out twice the other day when the kids didn't lock the sliding door) so I've been thinking about trying to train them to come to me when they're called.

Has anyone got any tips for this?

I know it's not like dog training, and I'm thinking about using a particular word and rewarding them with a treat when I use it. I'm thinking of starting off with them next to me and giving them the treat when I use a word, and then progessing from there.
I know it won't be a sure-fire solution, but I'm certain that it's better than chasing them around the back yard if they accidentally get out again...