In case you've ever wondered.
Back in the day when the Action Replay for the GameCube was first released, I snagged one up ASAP - because I'm a big cheater and I wanted the NES games in Animal Crossing. I'm not certian on the exact dates, but I seem to recall that the AR was released shortly after Animal Crossing.
Anywhoo - a while later after Wind Waker was released - it was discovered that, using the Action Replay, you could access "Test Rooms". Some of these rooms ranged from neat little things you could try out with ladders to no where to what I've since dubbed Zelda-Hell - large, brightly colored open spaces where the NPCs just stand in rows staring at a huge, brightly colored wall. Anywhoo, there are 14 (known) test rooms and each of these test rooms require codes that are about 72 characters long. I don't know how many of you have an Action Replay, but entering codes with the controller on this thing sucks - so, for the longest time, I never got to try out the test rooms.
Then, one day, I found the "PowerBoard". Basically a slightly-special PS/2 compatible keyboard with a PS/2-GCN adapter included, made by Datel (the Action Replay people) for use with the Action Replay and Phantasy Star Online. Anywhoo, I found it and it was cheap (like $5 - new). I was excited, I'd finally get to try out the Zelda Test rooms!
Boy, was I wrong. I got home to find out that my PowerBoard didn't work with my Action Replay because it was too old - however, after talking to Datel's customer support, they'd gladly allow me to purchase an updated AR disc - that has PowerBoard support - for about $20+Shipping. I couldn't see spending more money on this, so, sadly, I was still unable to play the Zelda test rooms. (Okay, actually, I could have played them all along, but again, controllers suck for typing.)
Forward to a while later and a friend in Japan found a slightly used ASCII keyboard for the GCN for what would be about $25 shipped. Considering these run about $70 new (not to mention shipping) and are kinda hard to come by here in the states (since they wern't released here), I was all excited because I'm a self-proclaimed hardware whore (I have a GCN Broadband Adapter and Modem Adapter and two ROBs...)
Well, this keyboard didn't work on the outdated Action Replay either (although I didn't expect it to). I still wish it worked on Animal Crossing though.
Now, forward to about 3-4 weeks ago - I read over at CAG that Circuit City has (newer) GCN Action Replays in clearance for $10! Yay! I go to my closest Circuit City and *bam* - one left, $10. I run it home and plug everything in and sure enough, the PowerBoard works. But the funny thing is, this one came pre-loaded with the Zelda Test Room Codes - meaning that I didn't have to enter them in, thus I didn't need the keyboard. Heh.
Aside from that, today I got my ASCII Keyboard out and plugged it in with the (newer) Action Replay and, sure enough, the Keyboard works. For what that's worth. 'eh, what can I say, I was bored.