And here, as promised, the poem.
After reading it in Assen, I added a line or two - I marked them here in blue:

To Letty

In the northernmost town of the Netherlands
Came together a big number of musical friends

On the first weekend of the month of May
In the year of the Lord twothousand and thray

We came together because Letty -
A young lady who is very pretty -

Wrote on the Mudcat: "Come together!
I will organize a Euro MudGather!"

From Germany, Belgium and the Juu Kay
To Groningen we all made our way

One rode on the bike, some on the train,
Some came by car, and some by plane.

When I to the Deliplein did come
Letty gave me a hearty welcome.

She did also wash my cycling shirt
which was full of sweat and full of dirt

Some of us did stay at your brother's place
Which will be known as Hotel Willem's Palace

The place is full of many mooses
In every shape and for all uses.

In the evening we were in a pub
To make music, to drink and for the grub.

We played the whistle, guitar and the mandolin,
Sung, listened or tuned the violin.

Each night at Willem's before falling asleep
Greg and Eric were discussing the advantages of sheep

Saturday morning Letty tried to find
Her watch that had hidden behind

The computer where Letty it found
After moving all the furniture around.

She also found money plenty
Of the old Guilders a note of twenty.

In the afternoon by a guide we were shown
The important places of Groningen town.

At the Cleopatra, two students, one of each gender
Cared for our thirst by playing bar tender.

The one was Willem, Letty's brother
And a friend called Monique was the other.

Again there was music and many a song
We had much fun many hours long.

I detected with a very big grief
That Wilfried is a little thief

I told him of this poem, and after short time
He had written and told his own little rhyme

Wolfgang did have luck too bad
For Saturday night he got no bed

He tried every hotel and hostel in town
In Willem's kitchen he was thrown.

On Sunday morning a big bunch
Of us went to Letty's parents for brunch

For which we are very grateful
I can say after having a mouth full

The food prepared by Abe and Janny
Was easily enough for twice as many!

On Monday morning when I went to unlock
My bike I got a mighty shock!

It was leaning there against the wall
and was not locked, not locked at all!

At long last now I am back home safely
After cycling through Holland and Germany bravely.

I think I speak for Wolfgang and Susanne,
For Frank and Iris and Ute und Anne,

For Erik the Viking, Skipjack and Ken
Herma, Wilfried, Ron and Glen,

And for the Dutch group's every member,
even if th names of them I can't remember

Also for Lady McMoo and Richard
And of course for myself, that is MudGuard

Thanks, Letty for the splendid organization
You are the pride of the Dutch nation!