What are some easy home made ideas I can use for my guinea pigs cage?

[Guinea Pigzzzzz]

I have 2 boars and they are in a cage that is 3x4 grids connected to a 2x6 section (10.5 ft. across and talk about spoiled, they are on a $1600 table lol), I have 5 different hidey places in there and numerous amounts of tunnels.
Every now and then I will throw a few newspaper pieces into the cage and toilet rolls stuffed with hay.
But that is about all, I know its a huge cage, but it seems so boring to me for some reason lol, they are always popcorning and running laps, but what else do guinea pigs love?
I have the space to do what I wish, I am cleaning their cage out at the moment and about to mix all of the tunnels and hideys up, so I wanna try adding something new, fun and easy to make.
Love watching them explore once they get back in there, they will be jumping all around going from tunnel to tunnel, hidey to hidey, food dish to food dish lol. (I have two kitchen areas on either end of the cage)

All ideas are greatly appreciated, thanks!

 

[twiams]

Are the pieces of newspaper safe?
I'd be worried about giving them to my piggies to chew on and eat because of the ink on them ? :x

Some toys and things my piggies love are ...

A treat dispensing ball handmade from toilet roll tube, they love it hanging from the top level, they take there time trying figure out where the smell is and then they manage to get it down.
Its just a case of cutting a toilet roll up to create 4 or 5 little loops and then piecing them all together, putting string around them and hanging it up.

This which is just another twist on a stuffed toilet roll giving more pieces to rip up and take apart.
http://www.theguineapigforum.co.uk/showthread.php?t=91111

Paper bags with some hay in them to sleep in and run in and out of and also to chew on.

Vegetable kebab's, these are a much funner way to do there veggies, just get some thick string and make holes in small veg pieces thread the string through and hang, don't worry about how high up you put pieces as they tend to slip down and the piggies will get on there back leg to get them aswell.

Dirty bed sheets, maybe not something to let them have in there cage but if you scrumple up a duvet sheet, i tend to do this when i change my bed covers, just let them out on the floor or something and just let them run around in the sheets, they tunnel around and look very cute !

Screwed up bits of just plain a4 paper, this is quite good because you can hide little treats in the crumpled up parts of the paper and it makes the piggies go crazy trying to find where the smell is coming from !

Also just hiding treats and things around the cage and letting them try to find them, i have a few hidey houses i use to put treats on top and they can smell them but cant see them |) they normally find them pretty soon though.

Hope thats of some use (:

 

[Guinea Pigzzzzz]

Thank you helped a lot, I am going to try all of that!