Verbs

As I said here, I think there is room for a radically simple universal second language, whose main characteristic would be that you could learn all of it (except vocabulary) in half a day.

This post aims to cover verbs in such a language.

The heading picture, from http://conjd.cactus2000.de/index.en.php, shows a conjugation table for one German verb, not even a difficult one.
How long before you could use that at normal talking speed?
For a bit more detail, you could try this. http://en.wikipedia.org/wiki/German_verbs
I think we can do better than that – or at least do something simpler & quicker to learn & be able to use.

Say our new language has a verb 'hit'.
You can guess what it means.
This one invariable word - & I want to stress that absolutely ALL words should be invariable – will be the infinitive.

It will also be the present tense, for any & every subject.
I/he/she/we/you/they/anybody hit.

I didn't mention the invariable word order: subject-verb-object.

To make a past tense, just add the invariable word 'did' after the infinitive.
I hit did.
She hit did.
Etc.

Note that, in general, all qualifying words should come after what they qualify, unlike in English.

To make a future tense, add the invariable word 'wil' after the infinitive.
I hit wil.
You hit wil.

Conditional?
Add 'wud'.
I hit wud.

Passive?
Add 'get'.
You hit get.

Combinations of passive & others are possible & obvious.
He hit get did.
You hit get wil.

Most languages have lots of additional tenses & moods.
Subjunctives, imperfects, continuous…
See the Wikipedia German link above.
They certainly add possibilities for subtlety & refinement.
I think a basic language can & should manage without.
In the interest of simplicity, above all.

So, in summary:
To learn any verb, you just learn one word, which stays invariable.

For every verb:
Future – add 'wil'.
Past – add 'did'.
Conditional – add 'wud'.
Passive – add 'get'.

That's it.
You know everything about every verb.