I think playpens really become frustrating to them once they can move around. DS was never interested in his playpen, so I tried to make sure there was a safe area for him in the house. It is a lot of work, but it is worth it. I think they need a certain amount of freedom to explore, otherwise everything is 'off limits' and that much more appealing! After a certain age, I don't really think you can do much to 'confine' them to a playpen, especially if they don't want to be in there!! Babies need to explore!
As for toys, TBH DS hardly took any interest in toys until at least a year. He'd pick them up and look at them, but no interest in playing with them. Non-breakable kitchen stuff really does make the best 'toys' at that age, somehow they know it is not 'theirs' but it is still safe to play with. What I did was rearranged my kitchen so all the accessible areas were filled with plastic bowls, tupperware, fun stuff for him to get at. He'd play with that all day (and still does)!
As they get older and move around more and more, it does become more of a challenge to keep them in one spot and interested in certain things. The world is just too exciting! Just part of the game I guess.
My house is really small, so it wasn't too hard to do, but I literally babyproofed the whole thing as best I could, and I just let him go everywhere. It was frustrating at first, but once he had explored every inch it became much easier to do things with him just wandering around the place. Now he is familiar with everything and doesn't get into as much trouble. Well.....he still gets into trouble, but I know what to do with him now! lol
