I started with a bookcase similar to these (sorry I forgot to take a picture before), smooth finish looks like fake wood panelling. I contemplated selling it and then purchasing something nicer but since it was probably going to be destroyed anyway by crayons, climbing, abuse, hitting it etc I figured it was good enough and sturdy enough (we also bracketed it to the wall so it couldn't be pulled down on anyones head)
If you were to just paint a piece of furniture with this kind of finish it would peel right off so you have to rough it up a bit, I was worried about what it would look like if I stripped off that laminate and if I ruined it I would have to go buy a new bookshelf anyways so I did some research (thank you google!) and found some great tutorials.
So following it to the letter, I gently sanded the piece down with my hand sander, just until the top layer of laminate was roughed up (ie. small white flakes appeared and the shine was gone) ***DO NOT sand down through the laminate to the pressboard or plywood)
Next wipe everything down with a damp cloth to remove the dust and let dry.
Apply a coat of ZINSSER 123 Primer I found this at Lowes for about $7 for a quart worked great with lots left over. I let the primer dry for 5 days to make sure it was cured well then painted everything with 3 coates of Mandarin Orange paint by Dutch Boy in Semi Gloss.