Reddit mentions of Kitty Mansions Memphis Cat Tree, Beige

Cardboard boxes with shredded paper, pieces of cardboard, paper towel rolls, and some hay stuffed inside with a tunnel attached is by far my buns' favorite toys. They love going in and ripping everything apart and finding hay/treats to eat. Bunnies love cardboard boxes in general. They'll rip them apart and move them around, chew on 'em, make hidey holes, climb on them. I'll even cut out some holes on the side of the boxes and stuff cardboard tubes frayed at the ends/stuffed with hay for them to have fun with.

Tunnels rank at number 2 favorite toy. Their favorite is the crinkley cat tunnels which have holes throughout them they can dart out. They like the crinkle noise too.

They love manipulating objects, hard plastic slinkies (not metal ones!) are fun for them ... and to watch, haha. Hard plastic baby rattles, baby keys, etc. Just no gel/soft plastic as it would be easy for them to bite and ingest.
http://wabbitwiki.com/wiki/Toys_and_Games This has an awesome list of toys and also places to buy bun toys. I've bought cottontail cottages, activity tables, rosewood activity trees, etc--buns love them all! But they are expensive for sure. The activity tables last forever but it would definitely be cheaper to build one !

Oh, also--I would recommend games like the Teach N Treat for mental stimulation as well: http://www.amazon.com/Hagen-Living-World-Teach-Treat/dp/B004HYW9B8/ref=sr_1_1?ie=UTF8&qid=1393474030&sr=8-1&keywords=teach+n+treat

There are tons of dog and cat games like that too that buns will love: http://www.amazon.ca/Trixie-4594-Products-Solitaire-White/dp/B0057G1WT0/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=3EH8O533V5DMS&coliid=I346NPTH7GATHZ

Also they love moving around these treat balls when you stuff em with pellets: http://www.amazon.com/Smarter-Toys-Treat-Inches-Colors/dp/B003ARUKTG/ref=sr_1_2?ie=UTF8&qid=1393474058&sr=8-2&keywords=treat+ball

They love games that have anything to do with eating/end result being eating. :P

http://www.amazon.ca/Kitty-Mansions-Memphis-Tree-Beige/dp/B0043Z0EUE/ref=wl_it_dp_o_pd_S_nC?ie=UTF8&colid=3EH8O533V5DMS&coliid=IHU58PNBHRME6 CAT TREES! Build your own if you want! Make sure if you buy one to cover any non-safe bun material.

I also got them one of these: http://www.amazon.ca/gp/product/B0038B2EKM/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1

http://www.amazon.ca/gp/product/B00005C5H4/ref=oh_details_o02_s05_i00?ie=UTF8&psc=1 Stack cups! Put treats between them and watch them knock them over and nom the treats. :)

http://www.amazon.ca/gp/product/B00000IZQP/ref=oh_details_o04_s01_i05?ie=UTF8&psc=1 They also like knocking these off.

http://www.amazon.ca/Super-Pet-Tropical-Fiddle-Stick/dp/B000HHO26E/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=3EH8O533V5DMS&coliid=I1Y9U0EEWOMV8N These things!

http://www.amazon.ca/Ware-711-Roller-Assorted-Colors/dp/B001CQFDJY/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=3EH8O533V5DMS&coliid=I3D5TZDNHU5HM8 This makes eating hay a bit more fun for them. :)

My boys love rolling around and destroying these: http://www.amazon.ca/Peters-Woven-Grass-Play-Ball/dp/B0009YJ3OG/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=3EH8O533V5DMS&coliid=I2VYO2771IW0LJ

Bunnies really enjoy long-term projects, which is why they like the dig boxes I described in the first paragraph so much. They dig and rearrange the boxes foreeever until I make a new one for them.