When I was in Minneapolis to pick up Andrew from the airport last week I was able to squeeze in a visit to Twin Cities Green, a really great little store that sells good stuff. I got two catnip slugs as recommended by Chaos and Mayhem Chris, plus picked up a couple pounds of Peace Coffee (not available in my area).
Later I emailed Chris to relay Hannibal's and En Esch's ecstatically enthusiastic thanks for the reccy:
I took some video of them when I first gave them the toys this afternoon. Then we all left to run some errands and eat lunch/dinner. When we returned three hours later both cats were in the same place, still licking their toys.
Andrew was filling their feeders when I initially gave them the toys. The feeders have been empty for a couple days, so both cats were pretty hungry and were prowling around him meowing, telling him to hurry up. But when I threw them the slugs, they totally ignored Andrew and the Science Diet. That speaks volumes for how great that 'nip is.