Mixed Bulbs a good idea?

So we have a planter box built into the front of our new place, that currently has nothing in it.

I had this idea to fill it up with soil, buy a bunch of mixed bulbs (like tulips etc) and then just plant them randomly and see what pops up come spring. Is this a good idea or just silly? I just like the aspect of it being a surprise as it all grows and flowers really! The space gets sun from mid morning to mid afternoon, and we are in Melbourne.