Traces of now-archaic technology in everyday life. I'm amused by the fact that the voicemail on my cell phone is signified by a symbol of a cassette tape -- even though, of course, there's no cassette tape involved.
→[More:] Similarly, I like how "phone" is still widely symbolized by the handset-on-rotary-dial-unit unit that's been almost universally displaced. Speaking of which, there's the very use of "dial" as a verb when we punch in the numbers to make a call -- even though there's no longer an actual "dial" to use.
What other examples can people think of?