It's fascinating to see product design passion projects from wealthy celebrities. Sometimes this can go bad—see Brad Pitt's furniture designs circa 2012—but Seth Rogen's Houseplant brand appears to be thriving.

Houseplant makes pot paraphernalia, some of which is designed by Rogen. The brand has expanded their product line since the last time we looked in on them, and I'm struck by their fanciful, clearly cannabis-inspired forms—and the sheer amount of people that see them. In a parallel universe where Rogen isn't famous, these items might be little-seen curiosities on Etsy. In this universe, Houseplant's Instagram has 657,000 followers. If just 1% of that audience buys Houseplant product, that's still 6,500 customers, which isn't nothing.

Being weed paraphernalia, Houseplant's offerings occasionally have quirky product copy. They also fall in the "forever object" category; most of the following are made of cast iron or concrete (the shipping costs must be horrendous).

Concrete Ashtray. "A hand-poured concrete ashtray that gets better over time, like fine-wine or emotional intelligence."

All-in-One Rolling Tray. "An ashtray, a really nice grinder, and a large surface for rolling. Literally a slab of gorgeous multi-color hand-poured concrete. Has slots to store Houseplant-branded rolling papers and tips."

Curvy Ashtray. "Hand-poured concrete. Deep ash-catching well. Five notches to hold five smokes."

Curvy Tray. Also made of concrete. My favorite line in the description: "Other curvy trays are bullshit."

Pebble Match Striker. "Looks like two stones stacked on top of one another, but is actually a match striker, a match holder, and an ashtray. Made out of incredibly sturdy cast iron. Almost unreasonably heavy (5.5 lbs). About the size of a softball if we had to approximate it. Leather base with embossed Houseplant logo."

Spike Ashtray, also made of cast iron. "7 joint-holding prongs for multiple joint-holding friends. Spikes inspired by pineapples, cacti and other spiky things. Spikes are mounted on a gasket for smooth spinning, and removable for easy cleaning."

Glass Grinder. "Colorful and sturdy borosilicate glass. Flat grinder pattern with divots to ensure the glass glides nicely while also grinding the weed. Ornamental pattern to match your grandmother's candy dish."

I gotta say—good for Rogen (and partner Evan Goldberg), for starting the company, keeping it going and expanding the product line-up. And you can be sure this is a man who uses his product: