This London Times cap-sleeve colorblock dress would look smart at the office with a blazer and sexy in the evening worn alone. You could also dress it up for attending a wedding or wear it to a graduation, as the guest or the grad! Though it's not exactly a splurge, this two-in-one dress costs $80 at Dillards.com.
Here's another version of this colorblocking style featuring the same bold blue hue on top and slimming black on the bottom, except this one's strapless. Save on the look at Forever21.com for a mere $24.80.