Mercutio: Nay, I am the very pink of courtesy.

Romeo: Pink for flower.

Mercutio: Right.

Romeo: Why, then is my pump well flowered.

Well, they aren't actually talking about pumps or flowers. There are so many sexual puns in this play—this is but one.

Romeo and Juliet begins with a triple pun on the word collier (coal vendor) which sound like choler (anger) and collar(hangman's noose). (I,i,1-4)

Here are some others:

Give me a torch. I am not for this ambling./Being but heavy(sad, weighing much) I will bear the light (brightness, weighing little). (I,iv,1-2)

Not I, believe me You have dancing shoes /With nimble soles. I have a soul of lead/So stakes me to the ground I cannot move. (I,iv,4-6)

...What dost thou make us minstrels? An thou makes mistrels of us, look to hear nothing but discords (off-key notes/disagreements). (III, i, 34-35)

We see the ground (earth/reason) whereon these woes do lie,/But the true ground of all these piteous woes/We cannot without circumstance descry. (V,iii,179-181)

Shakespeare wrote some great puns in Romeo and Juliet. I can't give you 10, but my favorite is Mercutio's pun in Act III when he realizes he has been fatally wounded:

...ask for me to-morrow, and you shall find me a grave man.

Grave meaning "serious," but, in this case, also meaning dead.