Can you print from film negatives without an enlarger?

Certainly. There's always contact printing, in which the negative is in direct contact with the paper, producing a print that is exactly the same size as the negative. All you need in that case is a controllable light source of the appropriate intensity (if it's too bright, you won't be able to adequately control the exposure time).

Needless to say, contact printing is of limited utility for small (35mm) and medium format photography. It's usually used in those cases to choose which negs to print "for reals" and/or to create an index card for a negative storage system (sheets in binders, etc.). When you step up to large format photography, though, contact prints will be of a size worth displaying, and because there are no additional optics (with their accompanying focus, contrast, aberration and distortion issues), the quality of the print can be breathtaking. Seeing a well-done 8x10 contact print up close is something you wouldn't soon forget.

EDIT: As an afterthought, I should probably note that you don't really need negatives either. With a sufficiently small light source (and a single LED would qualify if at a distance of more than a couple of feet) you can have a bit of fun with photograms as well. We used to use enlargers as the light source mostly to get reasonably collimated light from standard-sized light bulbs or cold fluorescents; but a discreet LED lit by a one-shot multivibrator would do the trick (they've gotten bright enough lately that electronic control of the on-time is pretty much necessary). And don't forget pinhole cameras with paper "negs".