The thrill of invention is the grease that lubes Tim Hawkinson's wheel.

Three years ago, when the Los Angeles artist made his local debut, New Yorkers fell in love with his eccentric art. Now the amazingly industrious Hawkinson is back at Ace Gallery with another idiosyncratic collection.

Using everyday materials like silver foil, cardboard tubes and popsicle sticks, Hawkinson brings a screwball flair to works that are variously huge and kinetic, small and visceral.

Sweetly blatant in their union of concept and process, most of these works are explained in detail on deadpan wall labels. This from Hawkinson's Pachyderm, a grand drawing consisting of a dense arabesque of curvy parallel lines: "Using my hand as a template, I plotted out a spiro-graphic choreography which describes the physical proportions of an elephant. I traced my hand, moved it slightly, traced it. The elephant trunk is at the top right."

Clearly, Hawkinson has a passion for tinkering and invention that's become fairly hard to find in more vanguard art.

In the current show, the main draw is Pentecost, inspired by the Christian celebration of the day that Jesus' 12 apostles received the Holy Spirit and were able to speak in different languages. The piece is a sprawling treelike structure of raw-umber-colored cardboard and paper, with 12 life-size mechanical figures sprouting from its branches. Each apostle is outfitted with an electronically controlled hammer attached to a single body part. As kneecaps, penises, elbows and tongues bang out a collective beat, Hawkinson's visitors wander under and among the expansive rhythms of the tree.

Pentecost fills Ace's central gallery. Among the other works are Untitled (Aerial Mobile), a profusion of television antennae hanging from the ceiling and rigged with sails like Captain Ahab's Pequod; Crow's Nest, a wall-size rubbing of Hawkinson's deck reconfigured into a sailing ship; and The Wall Chart of World History From Earliest Times to Present, a 33-foot-long abstract scribble that he calls a timeline.

With such size and girth, it's hard to imagine Hawkinson's grandiose contraptions finding a happier home than the tremendous 25,000-square-foot Ace. One can only imagine the large exhibition space uber-collectors Eileen and Peter Norton have for their private collections -- owners of many big Hawkinsons, they lent several pieces to the show.

Yet, much as Hawkinson loves the California macro-scale, he clearly relishes the micro-scale as well. One gallery contains a dozen common objects -- a hairbrush, a light bulb, a tape measure, a tube of toothpaste -- that Hawkinson has mechanically rigged to function as clocks. Two human hairs stuck in the brush, two filaments inside the bulb, the two twist-ties wired around a tape measure, and the toothpaste tube's cap and permadrip of paste are the ticking hands on each timekeeper. In Hawkinson's world, even clockwatching can be a good time.

In another room, Hawkinson eschews mechanics altogether. Three small works, displayed behind glass, portray an aged, translucent egg shell, the fragile skeleton of a tiny bird, and a simple feather. As the wall label reveals, the works Egg, Bird, Web and Feather are forged from the artist's fingernails, with a healthy dose of super glue. Delicate and primitive, they are every bit as bizarre and endearing as the clocks and Pentecost before them.

And perhaps this is Hawkinson's greatest strength: That with a resourceful and quirky vision, he democratizes conceptual art, making it fresh, accessible and a whole lot of fun.