The OP said 'meep', not 'honk'. I think we need some clarification as to whether it's a Road Runner, a Buick, or a locomotive sound that's desired. "Meep" makes me think Citroen. 
Then, getting into replicating something like these, makes me think of harmonics and wavetable synthesis. Or just using a wave or MP3 shield, and finding a recording of the desired sound. Whether that's simple depends on how you define simple.