Television producers have had a hard time adapting a party game like charades into a bonafide game show. Perhaps the most successful of these shows was Stump The Stars, aka Pantomime Quiz, which was a modest success in the 50's. Trying to duplicate the formula, however, has proven problematic, such that there hasn't been another attempt in 35 years (Celebrity Charades, which lasted 1 season).
Mark Goodson & Bill Todman thought they could make it work, and sold Showoffs to ABC in June 1975. The series lasted six months, however, a victim of a poor timeslot---airing at Noon (ET) in most markets---and a lack of promotion. Entertainer Bobby Van was not the first choice to host, though. That honor had gone to Larry Blyden, who had finished a run on What's My Line? and shot the pilot for Showoffs. Unfortunately, Blyden wasn't around when the series started, having passed away in an auto accident while on vacation. Thus, Van was given his first opportunity as an MC, and made the most of it.
I should note that at the time, the concept of a lunch hour newscast in my home area was still an idea, and that allowed some of these failed game shows to air in the Albany area. A great theme song, composed by the folks at Score Productions, which composed music for many of Goodson-Todman's shows in the 70's, was wasted.
Gilmore Box uploaded a sample open:
Van would bounce right back the very next year, resurfacing at NBC with The Fun Factory, which failed to get past a year as well. Three years later, Van was signed by Paramount to host a revival of Make Me Laugh, but that lasted a year and no more.