I tend to find them most itchy between about 15 minutes and 60 minutes after the bite (with a second phase about a day later) and I tend to get bitten in environments where I can't access a video game that quickly. :)

I should carry antihistimines around anyway since I swell up massively in response to bee stings and we're not quite sure if or when the reaction will turn anaphylactic. However, since I don't get hayfever, I'm massively antihistimine naive and usually don't get mosquito bites in situations where it's acceptable to go off and sleep either!

Interesting discoveries. Did you stumble across the suggestions that people of type O blood attract more bites?