Beyond the age where one can hide inside a cardboard box or under a sofa, hide-and-seek becomes a dangerous game. Rounds are won by people willing to risk terrible damage to property, perhaps climbing up onto the kitchen cabinets, or to their life, hiding inside an airtight fridge.
Video game hide-and-seek is dangerous in the other way: if they find you, you will die. Often one's hiding in plain sight, pretending to be an NPC or an inanimate object. SoulHunt [official site] is the second sort. One player's a murderous clown, and the rest are spirits who hide by possessing cups, magazines, brooms, frying pans etc., as you can see for yourself in a free alpha out now.
Inspired by the 'Prop Hunt' modes and mods you may have seen in games like Garry's Mod and TF2, SoulHunt lets players hide inside the props that clutter levels. As cups, flasks, pans, chairs, fire extinguishers, and so much more, they're trying to hide from the clown, who can track them by hearing their heartbeats. Hiders can move around to find good spots, or flee when their cover is blown, but I suspect a broom is no match for a murderclown. If the clown gits ya, murder.
Developers Wintercell Studios say on its Greenlight page that SoulHunt being standalone rather than a mod gives them "more freedom to take this gameplay to a next level", and that they're planning new maps, modes, hunters, and whatnot.
I think my favourite hide-and-seek game is still 1998's CrateDM mod for Quake 2. As its creator explains, "CrateDM pits opponents against each other in a room full of crates, and the players are crates." Possibly my favourite readme file, that one.