Jet Kwan (aka legoarchitecturemoc) built a series of Berlin landmarks to form Museum Island. The beautiful MOC includes the Berlin Cathedral, Altes Museum, and Alte Nationalgalerie.
Bricky_Brick designed and rendered an amazing History Museum. The museum covers various time periods and contains the tomb of Anubis, the Discobolus of Myron, the Sunflowers of Van Gogh, and many more historical items. The three story modular is also loosely inspired from the movie "A Night at the Museum".
Caroline Mockett ARPS built a wonderful Micropolis Air & Space Museum. This model has many great parts, including the Rocket Garden, Astronauts' Memorial, and LEGO Space colored building.
Anthony SÉJOURNÉ the A21 Tribeca Art Gallery. The New York inspired scene is composed of two buildings creating a nice slice of urban life. Inside are small workshops, a mini scooter garage, and of course, art.
Inyong Lee built an alternative model to 10214 Tower Bridge set. The three story modular is quite stunning, and houses a museum and bakery.
gonkius built a nanoscale version of the Guggenheim Museum in New York. Incredibly the model uses just 24 pieces.
The Museum of Mystery is another great creation by OrientExpress26. The building is half museum, half collection of curiosities and contains over 2400 pieces. Inside you can find many curious elements such as a Venus de Milo statue, jewels and Ella (the owner) herself.
chanedw built their first modular moc, a Star Wars museum called Bay 327. The museum is filled with cool Star Wars paraphernalia including helmets, ship replicas at the Death Star.
wrtyler, free of summer distractions, continued working on the National Gallery of Art (NGA) located in Washington DC. The museum will require 450 clear cheese slopes, which is why it is yet to be completed.
One of my favorite LEGO Ideas builders, Namirob, built and rendered an old winter museum. The three story building is nestled deep in a pine forest, and can be explored further by removing the modular floors.