Calendar widget width with Udesign

In your case the theme is styling the posts calendar in such a way that it’s ‘missing’ the event widget calendar.

In the theme’s style.css there’s the following:

#calendar_wrap {
    text-align:center;
}
#wp-calendar caption {
    margin:8px 0;
    font-size:1.4em;
}
#calendar_wrap td#prev a {
    text-align: left;
}
#calendar_wrap td#next a {
    text-align: right;
}
#calendar_wrap td {
    padding: 8px 12px;
}
#bottom #calendar_wrap td {
    padding: 6px 8px;
}
#calendar_wrap td#today {
    background-color: #8A8A8A;
    color: #FFF;
}
#calendar_wrap td#today a {
    color: #FFF;
    text-decoration:underline;
}
#calendar_wrap a {
    padding: 0;
    border: none;
}

just replace that with:

.eo-widget-cal-wrap,
#calendar_wrap {
    text-align:center;
}
.eo-widget-cal-wrap caption,
#wp-calendar caption {
    margin:8px 0;
    font-size:1.4em;
}
.eo-widget-cal-wrap .eo-widget-prev-month a,
#calendar_wrap td#prev a {
    text-align: left;
}
.eo-widget-cal-wrap .eo-widget-next-month a,
#calendar_wrap td#next a {
    text-align: right;
}
.eo-widget-cal-wrap td,
#calendar_wrap td {
    padding: 8px 12px;
}
.eo-widget-cal-wrap td
#bottom #calendar_wrap td {
    padding: 6px 8px;
}
.eo-widget-cal-wrap td.today,
#calendar_wrap td#today {
    background-color: #8A8A8A;
    color: #FFF;
}
.eo-widget-cal-wrap td.today a,
#calendar_wrap td#today a {
    color: #FFF;
    text-decoration:underline;
}
.eo-widget-cal-wrap a,
#calendar_wrap a {
    padding: 0;
    border: none;
}