Dayo, I have experience of this.
Ask will keep hitting your site hard and nothing will change, it will keep taking bandwidth - for now
Then at the next update loads of your pages will feature for all sorts of keywords, a number that you wont expect.
Its something to do with related content search - i would bet any money you have secured some links from some site that ask likes thats similar to your site content and thats what triggered it.
For now let it do its thing, its a short matter of time perhaps three/four months and you will start showing in the serps.
Two sites we work on that this happened on get as much traffic from ask as MSN! - if i knew how to start it off i would do it on other sites we work on to get them ranking but i dont and its a mystery but the link comment i made is relevent im convinced.
Good luck
