This Week, in Balloons

I'm coming back on Tuesday's train. Be there.
I'm bringing back a piece of London sky
That fell on me one sunny afternoon.
It came upon me, hurtling through the air
At speeds fantastic; first I heard a cry;
I heard a busker playing on a tune
That I had heard somewhere before, I think.
Be waiting for me, please. I'll need a drink.

Such strange things seem to happen on my trips.
They never seem to happen, though, to you.
My life has sprung up from the comic strips,
While yours is real. I don't know what to do.
I had the answers at my fingertips —
That is, until my fingertips turned blue.