KML-224 said:
I'm guessing this past Monday, as that's when it started to air on WCTX-TV (MY) channel 59 of New Haven, CT.
FWIW, the Wikipedia page about the show says you'd be correct.
http://en.wikipedia.org/wiki/Cash_Cab_(US_game_show)
"In the United States, Cash Cab episodes typically air on the Discovery Channel at 10:00am and 5:00pm to 7:00pm Eastern time on weekdays.[6] Beginning on
January 10, 2011, the show began airing reruns in syndication."
If I can find anything official about it, I'll post it here...
EDIT TO ADD: Indeed, there's a few places that had posts on it, but this is from Multichannel News which is probably most reliable of all I found so far. Notice it was originally scheduled to start in syndication in Fall 2010 - this article is from WAY back in 2009.
http://www.multichannel.com/article/366452-_Cash_Cab_Looks_For_Syndication_Fare.php
Oh, and here in my area it's listed on their website to air on WKRC's CinCW subchannel 11, 11:30, 12 and 12:30 on Sunday nights/early Mondays. That would displace syndicated "American Dad" re-runs. However, it doesn't show up until the 23rd-24th of January. I'll back this up with the appropriate links below.
http://www.local12.com/content/tv_listings/default.aspx (WKRC-TV 12 TV listings)
http://cashcab.mgm.com/ (The official Cash Cab syndication page with station listings)