[AmityvilleHams]

You're definitely lucky to have a robo!There are tons of wooden items out there which are very fun for robos,and it should be extremely easy to find resin things too

Great deals on cages and accessories for small animals at zooplus: Willow Tunnel

Luka Hamster Climbing Castle: Great Deals on Small Pet Cabins at Zooplus

Cabins & Houses: great selection at zooplus: Playhouse and Cabin Leif

Cabins & Houses: great selection at zooplus: Two Storey Cabin for Small Pets

Bridges & Stairs for Small Pets at zooplus: Wicker Bridge for Small Pets (Or just about any natural pet safe wooden bendable bridge!)

http://www.zooplus.com/shop/rodents/..._stairs/126804

http://www.zooplus.com/shop/rodents/...tunnels/193472

http://www.zooplus.com/shop/rodents/...tunnels/126828

You can probably find lots of other toys from Amazon and other pet websites,but it is definitely a good starting point for some different ideas!