喜不自禁

喜 = 壴 + 口 : Mnemonic symbol: 喜宴, wedding banquet.

Marie Curie is overjoyed to announce her marriage in the space station. She improvised a wedding banquet with nothing but mandarins and notifies everyone by beating a large drum very quickly with two mandarins.

不 = 丆 + 卜 : Bruno Bear (bu) is setting up a wind wheel (丆) with a voodoo staff (卜) in the space station's bathroom (Ø4). He also puts a "forbidden" sign (mnemonic symbol for 不) on it, to make clear that it may not (不) be stopped.

自 = 丶 + 目 : Mnemonic symbol: a hand mirror, which someone uses to look at themselves.

The Eye of Providence (目) is looking at itself (自) in a handheld mirror (自) in the space station's bathroom (Ø4). It think it's indeed looking very good, since Zorro (z) attached a petal (丶) to its eye (目).

禁 = 林 + 示 : There's a small forest of two Christmas trees (林) in front of the encampment ((e)n4). Although there's a sign clearly stating that it is forbidden (示) to touch the trees, Joan of Arc (ji) set up her guideon (示) so that it is supported by the two trees and she can practice pull ups.