cheer up, become jaunty, brighten, liven up, invigorate, smarten up, quicken, (re)vitalize, pep up, revive, inspirit, Colloq buck up:
The old lady perks up when her grandchildren come to visit. To perk up the party, Peter suggested we should all play a game.
Advanced English Dictionary
noun, verb +noun (also formal perquisite) [usually pl.] something you receive as well as your wages for doing a particular job: Perks offered by the firm include a car and free health insurance. + (figurative) Not having to get up early is just one of the perks of being retired. +verb[V] Phrasal Verbs: perk up perk sb<->up (informal) to become or to make sb become more cheerful or lively, especially after they have been ill/sick or sad: He soon perked up when his friends arrived. perk up perk sth<->up (informal) to increase, or to make sth increase in value, etc: Share prices had perked up slightly by close of trading. perk sth<->up (informal) to make sth more interesting, more attractive, etc: ideas for perking up bland food + Stencilling is a cheap and easy way to perk up old furniture.
Random quote: If you correct your mind, the rest of your life will fall into place.: Lao Tzu