One of the best tricks for knitting projects in a hurry is to make them with really bulky yarn. Bulky yarns are dramatic all on their own, so you don't have to do a lot of fancy stitch work to make a project that makes a big impact.
Also, bulky yarn is really warm, so it's perfect for last-minute scarf projects. My Bulky Ribbed Scarf doesn't really even need a pattern: just work 2x2 ribbing on as many stitches as you like until you're about to run out of yarn. If you want fringe for the ends, cut that first and you can use every inch of yarn you have -- or that you have time to knit, at least.
Another fantastic bulky scarf that I just love is the Ridged Stockinette Scarf. This pattern almost couldn't be easier but it is so pretty thanks to gorgeous yarn and a pattern with just the right amount of texture. And if you have a little extra yarn and time you can also whip up the hat project I call the Tam 'O Something, a top-down, super quick knitting hat that's sort of like a tam or a beret or something warm and pretty and good to knit. Whatever you call that.