If i gave my number to a guy, and providing that i liked them, i'd like to receive a text quite soon. If i gave the number out at night, it would be nice to get a text in the morning asking how i was after the night, etc. If i gave it out in the day, maybe that night, or the next day. I dont see the point in people waiting ages and playing it cool ... if you like somebody, dont waste no time. Leave it a good few hours, and then text her when you think shes not busy :o)