Push The Button, which centres around two families competing for a jackpot of £100,000 by participating in bizarre challenges, pulled in 6.57m (26.7%) between 7.45pm and 8.45pm.
Also on ITV1 Saturday night, Harry Hill's TV Burp logged 5.54m (23.3%) at 7.15pm, and 4.57m (18.6%) tuned in for All Star Family Fortunes between 8.45pm and 9.45pm.
Over on BBC One, Let's Dance For Sport Relief interested 6.51m (26.8%) between 7.15pm and 8.30pm, building on last week's opener, which had 6.25m (26.8%). The National Lottery: In It To Win It and Casualty followed, drawing 6.13m (24.8%) and 5.64m (23.6%) at 8.30pm and 9.15pm respectively.
BBC Two's coverage of the Winter Olympics averaged 1.4m (8.2%) between 7pm and 2am.
Fantastic Four logged 1.35m (5.5%) for Channel 4 between 8pm and 9.45pm, then 1.31m (6.8%) watched Under Siege across the 9.45pm-11.45pm period.
NCIS and CSI: New York took 1.43m (5.8%) and 1.96m (8%) for Five at 8pm and 9pm respectively.
Overall, BBC One dominated primetime with an average share of 25.3% to ITV1's 19.7%. BBC Two was third with 7.7%, followed by Five's 6.2% and Channel 4 with 5.1% (+1: 0.9%).
BARB ratings data supplied by Attentional