A simple test of strength that sometimes occurs when two alpha males shake eachother's hands for the first time. The process includes squeezing as hard as you can until one person gives up.
Chet hasn't met Brad yet? Get ready for a grip check!
When someone is holding an item (usually a drink) and you slap their hand(s) in an attempt to make the person drop the item. This is accompanied by yelling "Grip check!".
When a man will search for hours to find something that is laying out in the open on a table. Items are often easily found by a women.
Man: "I have been searching for hours for keys."
Woman: "You mean the ones sitting there on the coffee table?"
Man: "Where?"
Woman: "Right there in the middle of that table."
Man: "oh, must have been Male Pattern Blindness"