How can I get the second floor for my town's museum in ACNL?
Donate 20 items to the museum.
These must include at least one item from each category (Bugs, Fish, Paintings, Fossils).
Talk to Blathers on 14 different days.
Enter the museum when Blathers is thinking. Talk to him and he will propose the second floor as a public works project.
Donate to the museum 1 item of every category. In one category put in 20 or more bugs, fish, dino bones, or paintings. Talk to blathers every night past 7:00 PM. After 2 weeks Blathers should mention about a museum extension. You must be the mayor when talking to him. You may be unlucky and not have him talk about it for 2 or 3 years. I actually got mine in the 2 weeks. I hope yours comes soon too! :D
Donate 20 items to the museum, 1 in each Category. Talk to him everyday for a few weeks, and on a random day Blathers will be thinking. Talk to him, and he will mention the museum.
Donate 20 items to the museum. Also, talk with Blathers everyday for 2 weeks. Go into the museum the next day and he will be thinking about something. Talk to him and the second floor will be added as a PWP.
you donate 20 items to the museum than one day, when you come in the museum bathers, will be in a thinking position and suggest a public work project. He will most likely be in the position after 7 pm in the game.