Any scene with Jackie Chan fighting is awesome by default.
The first film
Although she was just a girl, SooYung didn't get kidnapped without a fight. She whips Sang with her bracelet, scarring his face, which she kicks him multiple times too before that.
Lee escaping Carter's watchful eye by hopping on street lights and jumping into vehicles (as they're moving!)
Carter, riding in a tow truck pulls up to the Consulate. Then he meets the guard Lee laid the smack-down on earlier. Also counts a funny moment before and after Lee takes off Carter's car steering wheel.
Carter: Hey, man, y'all see a little Asian dude about this height with a steering wheel on his arm?
Guard #1: Go screw yourself.
Carter: What did you say?
Guard #1: I said go screw yourself.
Carter: You take your little sensitive ass up there and let me in. Get out of the way! Don't make me get up out of this truck! Man, when I get up in there I'm slappin' somebody, I don't play that.
For that matter, Lee escaping Carter's car with his handcuffs by taking off his car's steering wheel and infiltrating the consulate.
The climax, full stop. A mexican standoff between Juntao's bodyguards and the FBI agents which gets turned on it's head when Carter gets a hold of Soo-Yung and demands they activate the detonator, then things go to hell with Lee mercilessly hunting down Juntao, getting a hold of him and lasting long enough that Juntao falls to his death. Special mention goes Carter and Sang doing a gun draw when Agent Russ was shot by Juntao. Then of course, Carter shot Sang directly in the heart.
Carter is really good at this sort of badass speech after he downright refuses his pending FBI badge from Agents Russ and Whitney.
Carter: You serious? I don't know what to say. It's like a dream come true. I got an idea though, I got an idea. Why don't y'all take that badge and shove it up your ass. All up in your ass. I'm L.A.P.D.
The second film
The battle on the bamboo scaffolding, with several mooks getting thrown off.
The massage parlor fight is definitely this with moments of hilarity.
The incredibly destructive fight in the Red Dragon Casino culminating in the use of an improvised zip-line.
The third film
The beginning, Kenji hits Counsel (now Ambassador) Han with a sniper rifle and Lee damn nearly catches up with him by traversing over a LA freeway via free running.
Carter and Lee interrogating the assassin, which is equal parts funny and impressive if you go with the interpretation that they had it all planned out: Lee deliberately gives Carter an empty gun, Carter "shoots" the guy to scare him and show that he means business, then Carter gets a clip from Lee so that he can load the gun right in front of the assassin, all obfuscated by Carter being Carter. It successfully gets him to crack.
Carter: That's right, Sister, call the Lord and tell him he's about to have some company! [...] Almost done, FORGIVE ME FATHER FOR I HAVE SIIIINED!
The final fight on the Eiffel Tower qualifies. Chiefly the Katana Vs Jian sword duel between Kenji and Li in a highly inversed national weapons scenario.
Carter taking down all of the triad goons, by HIMSELF, saving Soo-Yung, and killing The Dragon. Compare it to the first film where he was no slouch with a gun but a clumsy fighter at best, here he takes out mooks with as much ease as Lee.