After neglecting our local library for some time, the kids and I managed to get there yesterday. On the way I decided we should talk about library behavior. As the kids were all chiming in with things we do and don't do in the library, Builder said "I know! The 3 W's: Walk, Whisper and Wread!"
Of course, I had to quiet the comments by older siblings who know how to spell a bit better, but it worked! When one of them started to get a bit squirrelly, I just whispered "remember the 3 W's"! Now I'll have to spend the summer re-teaching some spelling rules, but it was worth it!