Three years or so ago we bought fabric so that I could make Sim a gown of some sort, then I got distracted and nothing happened. Three weeks ago we (OK, I) decided that we could get a gown of some sort ready in in time for a Yule Feast that we wanted to attend (hosted by the wonderful folks up at Ravenrook in Seattle). Now I don't sew quickly, everything else that I've put together has generally taken four to six months filling in on spare time as it comes up and definitely only getting rushed if it looks like the season will be over before I get a chance to wear it. So a gown from scratch to complete in three weeks seemed doable, but decidedly tight.
I didn't have a pattern, so best part of the first two weeks were spent drafting a pattern and fitting a muslin. That seems like a chore, but it really did make the third week much less stressful, and the end result was a gown that actually fit, looked good and was comfortable to wear. I might just buy a pattern next time, it really would have been a lot quicker.