The 99 is an ice cream cone, made with soft ice cream with a Cadbury Flake bar inserted in it and it's very popular during the British summer (!) - it's a vanilla-flavoured ice cream and you can get chocolate or strawberry syrup on it.
The ice cream van goes around and plays its little song so that the kids come out and get some ice creams... I have heard the ice cream van until 10 pm in some areas, but that is a different story...
This is me having a cheeky little 99 in Victoria Park, London - it was nice! And apparently, it has got a little bit of Italian history attached to it...
Ask.com says that:
A 99 ice cream was so called to appeal to the Expat Italians, who dominated the UK when the ice-cream was created. According to them, anything special or elite was named 99 after the monarch king of Italy's guard which comprised of 99 bodyguards. The ice cream is usually made of ice-cream served in a cone with a flake 99.
Wikipedia, instead:
Another possibility, is that it was named by Italian ice-cream sellers (many from mountainous areas in the Veneto, Trentino, Bellunese, and Friuli) in honour of the final wave of conscripts from the First World War, born in 1899 and referred to as "i Ragazzi del 99" - the Boys of '99. They were held in such high esteem that some streets in Italy were named in honour of them. The chocolate flake may have reminded them of the Alpine Regiment's hat, with a long dark feather cocked at an angle.
