Last night, headed upstairs for the evening, I decided to grab a few extra wanded cat teasers hiding in the front hall closet and take them upstairs. It wasn't a mistake, but we had serious scope creep.
In particular, we didn't have a extra "few" teasers, we had 10 of them. Sorting them evolved into pulling them out of the closet, untangling them, and tossing them into sorted piles on the floor, where the quality assurance team (Billy and Whitey) checked them out.
Whitey in particular was interested in the feathered wands, and after a basic play test I handed a wand to Katherine for Whitey to hunt on the stairs, while I chose a pom-pom ended wand for Billy to hunt on a cat tower. The end result was for the first time since we moved west, we had both boys seriously engaged in extended play in the same room.
It really only wound down when it seemed that Whitey was favoring his left rear leg. We had Whitey run several short sprints (kitty treats are quite useful for this), but the results were inconclusive. An hour later he was chasing his brother at full tilt, so we don't think he did anything serious.
Katherine and I agree, a good plan is more feather teasers for our resident bird watcher so he can work on his conditioning.