The word "aaaaaall" is an exaggerated way of saying "all". It emphasizes the idea of everything or everyone being included in a situation or a group. Full definition
Hands up if you want the recipe for this bad boy: Best breakfast I've had aaaaaall day (haha). (awesomeashild.com)
They've got three weeks before the end of the world, according to the radio disc jockey, so they'll be doing a «countdown to the end of days, along with aaaaaall your classic rock favorites!» (dvdtalk.com)