For my next stint as a DM i am planning on the group undergoing a series of tests based loosely around the types of giants and blanking on what to do about the greatest of them all, Storm Giants.

For the Hill Giants i plan on having the PCs (Level 8 Pally, Warlock, and Bloodhunter) encounter a group of hill giants that will attempt to bully and assert dominance over the group. I feel this will most likely end as a combat encounter but always leave things open for a chance to overcome this encounter through other means.

For Stone Giants, I plan on them assisting a Stone Giant in a competition of artistic skill that they can assist him, sabotage or destroy the other competition.

Fore Frost the group will need to display a great feat of strength. They could attempt to defeat the leader of the frost giant clan, go on a hunt to get him some new white dragon teeth for some new daggers or maybe hunt a Remorhaz. Or maybe they will think of some other way to display their streng5th to impress the giants enough to let the pass.

Fire Giant will require them to show him a weapon or armor of great craftmanship either from their own hands or assist him in making some himself. Also just demonstrating the quality  of their gear in a fight if they wish to try.

Cloud giants will either demand a large sum of the parties loot (basically all) since they feel they would be superior at managing these funds and is more in their rights or the party can engage in a series of wagers risking Max HP, Ability scores, Class Resources but perhaps walking away with more also.

Storm giants though i am at a loss to what i could do. Their lore makes them seem fairly passive to others and live lives of contemplation more than anything. So yeah, hoping for a few ideas on what i could do for this final giant based test.

When are you expecting to run this? I ask because a giant themed book is due out Aug. 15. It may have ideas for you.

running this In about two weeks

Maybe a recovery of lore test, locating an important text?  A series f riddles, based on logic and literal meaning kind of theme?  Maybe to read and properly interpret something, leading to a lost relic?  I think you're leaning toward a cerebral challenge more than muscles on this one.

If this is being presented by the giants themselves, then consider dropping a little lore into each of the encounters - in the Hill giants, have one of them (as part of their banter) have a little internal argument of "I'm the strongest so I'm boss" with everyone else jeerign and saying it's actually Burt as he's tallest, "'cos we're called giants, not muscles!". For the stone art, have one give some lore about their art - "we only carve likenesses of ourselves from stone, never wood". That sort of thing, that could get lost in the moment.

Once they have gone through all of them, they meet the Storm Giant. They expect a trial, but instead, he asks them what they have done so far.

And then, he asks them: "And what have you learnt?"

They need to remember 4/5 of the lore tidbits to pass, and if they remember 5/5, then they get a gift as well - the ability to speak giant.