I asked my 6 year-old to pick up his toys so I wasn't stepping on something every time I went into his room. I specifically said that the larger toys, which don't fit in the basket or on his shelf, need to go back in the toy box in the playroom. Approximately 5 minutes later he came out and announced, "I cleaned!"
When I walked into his room he proudly pointed out, "I cleared you a path so you can put my clothes in my dresser! Isn't that good?"