No word on any upcoming events right now. DVC is opening a new sales center in New York in a few weeks so the focus may shift over there briefly. Still, they do tend to hold events every 6 months or so. There may still be one before the end of the year.
Whether they are holding an event or not, the Chicago location is fully equipped to give you all of the info you need on DVC. They have full-size mock-ups of the guest rooms you can tour and a fully-trained sales staff.
The special events do usually have some extra benefits for buying, but it's your call as to whether you want to wait or not. DVC has very good prices right now, particularly on the Grand Californian, Saratoga Springs and the Animal Kingdom Villas. There's no way of knowing whether the prices offered at the next sales event will be lower than the current offerings.