"merry evening" is a correct and usable phrase in written English.
For example, you could use it to sign off a friendly letter, such as: "I hope you have a merry evening! Warmly, [Your Name].
Not until the meat course was under way did he discover that he had entered the wrong house, and by that time it didn't seem worth changing so he stayed and had an unusually merry evening.
These poor people's bad luck was my comedy gold, as I spent a very merry evening repeating the phrase, "So, what you're saying is… Mos def-initely won't be coming?" The Sunday was all about the hamam, so we left our resentful-looking baby with a very experienced sitter for the day.
Pepys sadly recorded another busy day – up betimes, work meetings, dined at home, boat up the Thames to Whitehall via an encounter with an old amour ("Je did baiser elle") and finally with his long-suffering wife and a friend to walk in the park and a merry evening at The World's End pub, "and so home late".
Waiting for a band to take the stage like, we did for this merry-troupe last night, can be an exhausting and irritating ordeal; when things are in sync, however, Edward Sharpe and the Magnetic Zeros exude a bright and warm energy that really takes hold of the audience.
The group dance known as the Ballabile from the first act of "Napoli" looked equally merry in the afternoon and at night, and the male ensemble was especially sprightly.
Then the India openers, Ajinkya Rahane and Shikhar Dhawan, made merry in the afternoon sunshine to take their team to 212 for one and complete the humiliation.
We were a merry party that night at dinner pistou, grilled langoustines and the ubiquitous Provençal rosé wine.
And all the Giants lovers in the town of San Francisco ate and drank and made merry far into the night.
After what the United States attorney called "a merry chase through the night," the F.B.I. seized the Seales in Hackettstown.
The scene at Hi Dive, a bar on the Embarcadero tucked under the Bay Bridge, was a merry one late Tuesday night.
