Neither midweek nor Clarendon, but the DC Travel and Adventure Show is at the Convention Center next weekend (22-23 February). Tickets are 15 bucks at the door, but Goldstar has them for 5, plus a service fee.

I am planning on going on Sunday. If anyone is interested, either brunch beforehand or an afternoon happy hour would be do-able. It's a short walk to the Chinatown-Gallery Place / Penn Quarter area, which has numerous options.