Why not? Low-cal espresso?
No no, I'm talking about illuminating your cup under the portafilter. It irritates me not being able to see well down in the work area of the machine. I used to have a lamp with a gooseneck next to my machine, but since moving to a stainless work table I could no longer use that. Here is a solution that works great for me, cost about €3.50 and requires no installation, wiring or switches. It is a little, round LED lamp from Osram (there are probably other brands) called a DOT-it Waterproof. You turn it on and off by pressing in the middle of the lens and it is magnetic so it sticks the underside of the machine. I can recommend it without hesitation.
There is a YouTube video about this and other things (more espresso videos to come) here.