Checking for collisions outside OnCollision*

Is it possible to check if two game objects are colliding outside of the provided OnCollision and OnTrigger events?

At the moment I am setting a flag in the relevant OnTrigger event, but I was wondering if there is an alternative way of checking for collisions that can do away with the flag. Something like this.collider.IsColliding(gameObject.collider) perhaps.

Search for raycasting!