Shellen recently completed revisions on The Quality of Respect, her take on Shakespeare's The Merchant of Venice, the fables on which Merchant was based, and the life of the Ghetto Nuovo, the world's first Jewish ghetto. Her two plays, Wall Posters and War Orphan, were both developed in the Playwright/Directors' Workshop of the Actors Studio. Her play, Imperfect Flowers, originally written for Gretchen Cryer and Jimmy Wlcek, played to rave reviews in Omaha, Nebraska, as part of SNAP!Fest (“a night when acting and lights and music and a glorious script all come together into something bordering on magic,” Omaha World-Herald). The first act of the play, a one-act entitled Anthesis, also received raves in L.A. when it played at the West Coast Ensemble. Her first musical in NYC, Molly's Daughters, was commissioned by American Jewish Theatre. Other plays and musicals have been performed in productions and staged readings at the Public Theatre, Henry Street Settlement, Manhattan Class Company, Hubbard Hall, and many other venues.

As a director, Shellen has directed numerous plays, musicals, and cabaret acts in productions, workshops, and readings, including the 28th-34th Annual Bistro Awards, Passageways by Amy Oestreicher at Here Arts Center, Tyler's Theory of Love by Stuart Warmflash for the EAT Festival, Buck Naked by Gloria Bond Clunie for Ivoryton Playhouse's Women Playwrights Initiative, Loyalty by Brenda Foley for the Think Fast Festival in Maplewood, NJ, This Is Harriet's Play and Essie Finkelstein by Leah Kornfeld Friedman at 13th Street Repertory Theatre, Door Opens Walk Thru by Susan Merson at 13th Street Repertory Theatre, Between Pretty Places (a musical Ghost Story by Susan Merson with music and lyrics by Lubin and additional music by Matthew Gandolfo) at Pacific Resident Theatre in Venice, CA and at Here Arts Center in NYC, and The Sarah Play at the Davenport Theatre. She is currently in development with two plays by Lanie Robertson, three by Stuart Warmflash, and Anel Carmona's Green Mist.

Shellen has been onstage—as both a singer/songwriter and an actor— for years, both in and out of New York City. She and her songs have been featured on radio (Woody’s Children on WQXR-FM, a one-hour special on WBAI-FM, and various shows on WABC, WOR, and WEVD-FM), cable television, and in Milos Forman's first American film, Taking Off. Mother/Child, her one-woman musical, was called by WBAI-FM: “a dynamite show about the joys, agonies, conflicts, and concerns of combining new parenthood, person-hood, and artist-hood.” Other performing credits include stage (most recently "The Flood" in The Vagina Monologues at Here Arts Center directed by Andrea Bertola), screen (including principal roles in the films Green Card and Taking Off), and television (currently developing the role of Luanne in Amanda Cole's High Falls).

As a vocal and acting coach, she teaches professionals for stage, screen, and recordings, and has taught and performed at a number of colleges and professional and private schools, most notably Bennington College, her alma mater, where she was a guest artist in the Black Music Division for Bill Dixon. She has coached actors in starring roles in theatre and on television, and for auditions in all media. As a teaching artist, she has not only developed and taught programs for schools, but worked as a consultant and professional developer for a number of institutions, including Teachers College, Marymount Manhattan College, Lincoln Center Institute, and Nashville Institute for the Arts.

Her philosophical musings on artistry as a means of understanding ourselves and living more deeply, truly, and meaningfully have been read by thousands in her weekly think piece, the “Monday Morning Quote” which goes out on the internet first thing each Monday to an ever-increasing list of subscribers. She is also the resident writer/philosopher for The Village Yontif. Her eloquence on these issues have also been read by many more in five cover pieces for Back Stage, the Performing Arts Weekly.

Shellen is a member of DG, BMI, SDC, and most performers’ unions, and is the Co-President of the League of Professional Theatre Women, Past President and 1st VP of the Women in the Arts & Media Coalition, and chair of the Women Playwrights Initiative of the National Theatre Conference.