John Travolta’s 70th birthday was one to remember! The Saturday Night Fever alum took to Instagram on Sunday, February 18, to reveal he spent his special day with his son Ben,13, out on the slopes. “This was my favorite birthday gift today. Seeing my son Ben ski to a new level! I’m so proud of him,” Travolta wrote alongside a video of his kiddo skiing down a mountain. In a clip shared to the Grease star’s Instagram Story, Travolta blew out the candles on his cake while his dog, Peanut, gave him a kiss. The proud dad’s daughter, Ella, 23, shared an Instagram tribute alongside a sweet throwback …