This happened to me a couple of weeks ago, I got linked by tuaw.com and then digg.com on consecutive days resulting in about 24,000 visits in 48 hours and 18,000 visits in 24 hours.
Traffic went down pretty quickly afterwards, it was 5,000 visits the day after, 2,000 the next day but when it got to about 1,500 it stabilised there. I am getting between 800 and 1500 visits a day and I have been in the top 10 blogs on every day that I have made a post since then (If I don't post, I slip off in < 12 hours).
My example (like Danny's) is quite a "pure" example because until I got linked from tuaw/digg I had almost zero visits (maybe 3-15 visits per day, from friends).
I have yet to be slashdotted :)