The funniest episodes that I remember are 3, 20 and 26. Those are full of good jokes. If I should pick one it was in ep 26 when Naruto introduces Sasuke for school newspaper:

"This is a lame guy known as Uchiha Sasuke." (There's shown moments when Sasuke is in troubles.) "He's pretty famous as the survivor of the Uchiha Clan but in actuality he's a pathetic guy, as you can see." (Sasuke running to bathroom in ep 3 but then he transforms back into Naruto) "Ah! That was when I transformed into him." Funny one.