I have seen it written here and there that there are insufficient good patterns to knit for a baby boy around, so I thought I would make a list of some of my favourites, with a short list of further sources at the end. I will admit I have not yet knit all of these patterns, but Ravelry has full details if you wish to read feedback from others before choosing. Hope this provides some inspiration.
Ideal for boys or girls, really do stay on and perfect use for those bits of leftover 4ply
A brilliant, fun knit, providing you're willing to think a bit to get through the pattern. Shows off stripy yarns wonderfully.
3. Pebble (Henry's Manly Cobblestone Vest)
One of the most practical baby knits for a small baby
5. Baby Poonam
Too cute, like a little old man jumper
8. Epsilon vest
A cardigan which handily comes in a lace or cable version, suitable for either sex.
Good sources for boys' knits:
Sirdar - do a lot of baby patterns, a good proportion of them for boys. Some of them sell online on patternfish
Petite Purls - like knitty.com for babies and children, some wonderful patterns.