Ethilrist.
:o That happened to me too. “Gwen” is surprisingly hard for folks to understand, so I go with “Wendy” or “Amanda” or something self-explanatory. Of course I did that once when wearing a big “Gwendolen” tag. Thankfully, they didn’t seem to notice.
Oh so that’s what an alias is! I’ve always wondered!
Yes, I could probably think of a couple, if you gave me enough time. One of them being “heartsplayer” 
Otto Iris
I’m also fond of Johnny Cockrocket.
It’s pronounced, ca-CROCK-et.
For years I’d sign in at restaurants as Vladimir. My real name is a pain, so I needed something else. The gender bending was just a perk.
I guess the problem was that she realized she’d married the wrong guy from his circle of friends; she shoulda picked you. 
My last name is a PITA like that. So I use “Fox”, especially if the host(ess) is bad at English.
Pickles Beaversnatch.
Well, not really, I just wanted to try that one out.
That’s Dr. Buck Naked to you.
My favorite is Oliver Faltz, as in “I love my wife in spite of…”
If you’re going to be served in alphabetical order, Baldwin Aaberley is good.
For a restaurant where the hostess calls out “the Jones party,” go with Donner or Wilde.
Finally, there’s Hanover Fiste and Anita Nothershot.
Hojo Hominigrits
For a few years now I always use “Donner” at restaurants just to hear them announce “Donner - party of 5. Donner - party of five”.
(And sometimes I pad the number by one or two if it looks like a long wait)
Bob B. Bobb.
My IRL first name is the same as a book of the Bible (OT), and my last name is that of a Napoleanic battle, so I usually use a variation of those, like Samuel Austerlitz, Amos Borodino, or Jeremiah Marengo.
I’m easily amused.
Waay back in the 70s I knew a guy who did that. He always picked very ethnic names where the first and last were utterly incompatible
Jose Fujitsu was one of his favorites. As was Vladimir Rodriquez.
Nowadays real blended ethnicities aren’t so rare. Back then? Lots rare. And since he was a he there wasn’t even the out of the last name being her married name.
Good fun.
I’m female. For years, I used to visit a commercial building on Manhattan’s West Side that had the sleepiest security guard I’ve ever seen. And I routinely signed, fairly legibly, in as Adm. Horatio Hornblower, RN (Ret.) I mean, I did this for about four years. Finally, one afternoon I stepped off the elevator on the 5th floor and the receptionist at Martin Audio looked up and said sternly “Admiral Hornblower?” They still sold me the tape recorder, however…
On a related note, when telemarketers call, I just explain, in French, that no, my name is Jeanne d’Arc, and “Parlez-vous Francais, M’sieur?” Out of the last hundred calls, I’ve gotten one telemarketer who blurted out “JOAN OF ARC?!”
Nicola Bonanno.
I always use the name of one of the old high-school bullies back in West Texas. He may have a lot to answer for by now.