Play under the stars
Play Ein Kleine Nachtmusik (a little nightmusic) as the sun sinks behind the horizon.
If you have an instrument (preferably portable, unless you fancy dragging an organ outside!) take it out on a warm night and play as the sky turns gorgeous shades of pink and orange.
Get creative and write your own piece of music. Unleash your inner Beethoven and compose an ode to the evening; channel Mozart and write a song for the sky; or jam out and play a gig for the grass.