I fell in love with the orcs very quickly, and the first mini-adventure I ran included some orcs in an underground river. They made great enemies - cunning at times, but mostly brutal and barbaric.They were easy enough to fight at the lowest levels of game play, but they were tough enough - and interesting enough - to use as good monster thugs through mid-level gaming (4th to 7th levels).
The Basic Set's accompanying adventure, Gary Gygax's The Keep on the Borderlands, featured a linked set of orc lairs at a locale known as the Caves of Chaos. It brought a lot of the monsters' characteristics to the table. The orcs weren't just a bunch of statistics; they played like orcs. For example, a sentry watched one cavern entrance by poking his head through a secret wall opening to rest it upon a shelf of head trophies; the two chieftains did not trust each other and would take over their ally's clan if the players killed or captured him.
The adventure really did a great job of bringing out the flavor of all the monsters that it featured. It had about a dozen or so cave lairs, mostly inhabited by an assortment of tribal humanoid warbands, but they each behaved differently.
Note: The cover to The Keep on the Borderlands (see right), features old school orcs, complete with boar-like tusks. One of the iconic images of the game is that elf shooting the orc in the chest with an arrow.